215904 has 48 divisors (see below), whose sum is σ = 613872. Its totient is φ = 66048.

The previous prime is 215899. The next prime is 215909. The reversal of 215904 is 409512.

It is an interprime number because it is at equal distance from previous prime (215899) and next prime (215909).

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×215904² = 93229074432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215909) by changing a digit.

215904 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1162 + ... + 1334.

It is an arithmetic number, because the mean of its divisors is an integer number (12789).

2²¹⁵⁹⁰⁴ is an apocalyptic number.

215904 is a gapful number since it is divisible by the number (24) 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 215904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (306936).

215904 is an abundant number, since it is smaller than the sum of its proper divisors (397968).

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

215904 is a wasteful number, since it uses less digits than its factorization.

215904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 191 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 215904 is about 464.6547105109. The cubic root of 215904 is about 59.9911097939.

The spelling of 215904 in words is "two hundred fifteen thousand, nine hundred four".