21010636 has 12 divisors (see below), whose sum is σ = 36803200. Its totient is φ = 10495440.

The previous prime is 21010609. The next prime is 21010663. The reversal of 21010636 is 63601012.

It is an interprime number because it is at equal distance from previous prime (21010609) and next prime (21010663).

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, 4501 + ... + 7891.

Almost surely, 2^21010636 is an apocalyptic number.

It is an amenable number.

21010636 is a deficient number, since it is larger than the sum of its proper divisors (15792564).

21010636 is a wasteful number, since it uses less digits than its factorization.

21010636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4944 (or 4942 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 21010636 is about 4583.7360307941. The cubic root of 21010636 is about 275.9389874237.

Adding to 21010636 its reverse (63601012), we get a palindrome (84611648).

The spelling of 21010636 in words is "twenty-one million, ten thousand, six hundred thirty-six".