21065836 has 12 divisors (see below), whose sum is σ = 40216680. Its totient is φ = 9575360.

The previous prime is 21065831. The next prime is 21065843. The reversal of 21065836 is 63856012.

It is a junction number, because it is equal to n+sod(n) for n = 21065798 and 21065807.

It is not an unprimeable number, because it can be changed into a prime (21065831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 239341 + ... + 239428.

It is an arithmetic number, because the mean of its divisors is an integer number (3351390).

Almost surely, 2^21065836 is an apocalyptic number.

It is an amenable number.

21065836 is a deficient number, since it is larger than the sum of its proper divisors (19150844).

21065836 is a wasteful number, since it uses less digits than its factorization.

21065836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478784 (or 478782 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 21065836 is about 4589.7533702804. The cubic root of 21065836 is about 276.1804288269.

The spelling of 21065836 in words is "twenty-one million, sixty-five thousand, eight hundred thirty-six".