20993636 has 12 divisors (see below), whose sum is σ = 36785280. Its totient is φ = 10483560.

The previous prime is 20993633. The next prime is 20993663. The reversal of 20993636 is 63639902.

It is a self number, because there is not a number n which added to its sum of digits gives 20993636.

It is not an unprimeable number, because it can be changed into a prime (20993633) 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, 821 + ... + 6531.

It is an arithmetic number, because the mean of its divisors is an integer number (3065440).

Almost surely, 2^20993636 is an apocalyptic number.

It is an amenable number.

20993636 is a deficient number, since it is larger than the sum of its proper divisors (15791644).

20993636 is a wasteful number, since it uses less digits than its factorization.

20993636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6634 (or 6632 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 38.

The square root of 20993636 is about 4581.8812730144. The cubic root of 20993636 is about 275.8645453089.

The spelling of 20993636 in words is "twenty million, nine hundred ninety-three thousand, six hundred thirty-six".