21915636 has 24 divisors (see below), whose sum is σ = 52786944. Its totient is φ = 7069440.

The previous prime is 21915629. The next prime is 21915679. The reversal of 21915636 is 63651912.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21915597 and 21915606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29085 + ... + 29828.

It is an arithmetic number, because the mean of its divisors is an integer number (2199456).

Almost surely, 2^21915636 is an apocalyptic number.

It is an amenable number.

21915636 is an abundant number, since it is smaller than the sum of its proper divisors (30871308).

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

21915636 is a wasteful number, since it uses less digits than its factorization.

21915636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58951 (or 58949 counting only the distinct ones).

The product of its digits is 9720, while the sum is 33.

The square root of 21915636 is about 4681.4138889870. The cubic root of 21915636 is about 279.8453057068.

The spelling of 21915636 in words is "twenty-one million, nine hundred fifteen thousand, six hundred thirty-six".