21612236 has 12 divisors (see below), whose sum is σ = 40046328. Its totient is φ = 10170432.

The previous prime is 21612229. The next prime is 21612259. The reversal of 21612236 is 63221612.

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, 158846 + ... + 158981.

It is an arithmetic number, because the mean of its divisors is an integer number (3337194).

Almost surely, 2^21612236 is an apocalyptic number.

It is an amenable number.

21612236 is a deficient number, since it is larger than the sum of its proper divisors (18434092).

21612236 is a wasteful number, since it uses less digits than its factorization.

21612236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 317848 (or 317846 counting only the distinct ones).

The product of its digits is 864, while the sum is 23.

The square root of 21612236 is about 4648.8962130811. The cubic root of 21612236 is about 278.5479075723.

Adding to 21612236 its reverse (63221612), we get a palindrome (84833848).

The spelling of 21612236 in words is "twenty-one million, six hundred twelve thousand, two hundred thirty-six".