213931440 has 120 divisors (see below), whose sum is σ = 736077888. Its totient is φ = 55649280.

The previous prime is 213931427. The next prime is 213931489. The reversal of 213931440 is 44139312.

213931440 is a `hidden beast` number, since 213 + 9 + 3 + 1 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×213931440² = 91533322040947200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25897 + ... + 33143.

Almost surely, 2^213931440 is an apocalyptic number.

213931440 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 213931440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (368038944).

213931440 is an abundant number, since it is smaller than the sum of its proper divisors (522146448).

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

213931440 is a wasteful number, since it uses less digits than its factorization.

213931440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7307 (or 7298 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 213931440 is about 14626.3953180543. The cubic root of 213931440 is about 598.0785197582.

The spelling of 213931440 in words is "two hundred thirteen million, nine hundred thirty-one thousand, four hundred forty".