213723440 has 80 divisors (see below), whose sum is σ = 575201280. Its totient is φ = 72334080.

The previous prime is 213723421. The next prime is 213723449. The reversal of 213723440 is 44327312.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (213723449) 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 15 ways as a sum of consecutive naturals, for example, 41825 + ... + 46655.

It is an arithmetic number, because the mean of its divisors is an integer number (7190016).

Almost surely, 2^213723440 is an apocalyptic number.

213723440 is a gapful number since it is divisible by the number (20) 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 213723440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287600640).

213723440 is an abundant number, since it is smaller than the sum of its proper divisors (361477840).

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

213723440 is a wasteful number, since it uses less digits than its factorization.

213723440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4930 (or 4924 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 26.

The square root of 213723440 is about 14619.2831561606. The cubic root of 213723440 is about 597.8846248185.

The spelling of 213723440 in words is "two hundred thirteen million, seven hundred twenty-three thousand, four hundred forty".