21915236 has 12 divisors (see below), whose sum is σ = 43830528. Its totient is φ = 9392232.

The previous prime is 21915221. The next prime is 21915253. The reversal of 21915236 is 63251912.

21915236 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21915199 and 21915208.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 391316 + ... + 391371.

It is an arithmetic number, because the mean of its divisors is an integer number (3652544).

Almost surely, 2^21915236 is an apocalyptic number.

It is an amenable number.

21915236 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21915236 is a wasteful number, since it uses less digits than its factorization.

21915236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782698 (or 782696 counting only the distinct ones).

The product of its digits is 3240, while the sum is 29.

The square root of 21915236 is about 4681.3711666562. The cubic root of 21915236 is about 279.8436031354.

The spelling of 21915236 in words is "twenty-one million, nine hundred fifteen thousand, two hundred thirty-six".