20864636 has 12 divisors (see below), whose sum is σ = 39321912. Its totient is φ = 9629808.

The previous prime is 20864617. The next prime is 20864647. The reversal of 20864636 is 63646802.

It is a junction number, because it is equal to n+sod(n) for n = 20864596 and 20864605.

It is a congruent number.

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, 200570 + ... + 200673.

It is an arithmetic number, because the mean of its divisors is an integer number (3276826).

Almost surely, 2^20864636 is an apocalyptic number.

20864636 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20864636 is a deficient number, since it is larger than the sum of its proper divisors (18457276).

20864636 is a wasteful number, since it uses less digits than its factorization.

20864636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401260 (or 401258 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 20864636 is about 4567.7823941164. The cubic root of 20864636 is about 275.2983472806.

The spelling of 20864636 in words is "twenty million, eight hundred sixty-four thousand, six hundred thirty-six".