213128909 has 8 divisors (see below), whose sum is σ = 256395840. Its totient is φ = 173066976.

The previous prime is 213128893. The next prime is 213128911. The reversal of 213128909 is 909821312.

213128909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 213128909 - 2⁴ = 213128893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213128009) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 801104 + ... + 801369.

It is an arithmetic number, because the mean of its divisors is an integer number (32049480).

Almost surely, 2^213128909 is an apocalyptic number.

It is an amenable number.

213128909 is a deficient number, since it is larger than the sum of its proper divisors (43266931).

213128909 is a wasteful number, since it uses less digits than its factorization.

213128909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1602499.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 213128909 is about 14598.9352008974. The cubic root of 213128909 is about 597.3297160096.

The spelling of 213128909 in words is "two hundred thirteen million, one hundred twenty-eight thousand, nine hundred nine".