21215832 has 32 divisors (see below), whose sum is σ = 57862080. Its totient is φ = 6428960.

The previous prime is 21215827. The next prime is 21215833. The reversal of 21215832 is 23851212.

It is a super-2 number, since 2×21215832² = 900223054904448, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215833) 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, 39918 + ... + 40445.

It is an arithmetic number, because the mean of its divisors is an integer number (1808190).

Almost surely, 2^21215832 is an apocalyptic number.

21215832 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21215832 is an abundant number, since it is smaller than the sum of its proper divisors (36646248).

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

21215832 is a wasteful number, since it uses less digits than its factorization.

21215832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80383 (or 80379 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

The square root of 21215832 is about 4606.0646977653. The cubic root of 21215832 is about 276.8343790482.

The spelling of 21215832 in words is "twenty-one million, two hundred fifteen thousand, eight hundred thirty-two".