213128916 has 144 divisors (see below), whose sum is σ = 673180032. Its totient is φ = 51068160.

The previous prime is 213128911. The next prime is 213128921. The reversal of 213128916 is 619821312.

213128916 = 15² + 16² + ... + 861².

213128916 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (213128911) and next prime (213128921).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a zygodrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213128911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 131326 + ... + 132938.

Almost surely, 2^213128916 is an apocalyptic number.

213128916 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213128916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (336590016).

213128916 is an abundant number, since it is smaller than the sum of its proper divisors (460051116).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

213128916 is a wasteful number, since it uses less digits than its factorization.

213128916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1662 (or 1649 counting only the distinct ones).

The product of its digits is 5184, while the sum is 33.

The square root of 213128916 is about 14598.9354406409. The cubic root of 213128916 is about 597.3297225492.

It can be divided in two parts, 21 and 3128916, that multiplied together give a square (65707236 = 8106²).

The spelling of 213128916 in words is "two hundred thirteen million, one hundred twenty-eight thousand, nine hundred sixteen".