20720636 has 6 divisors (see below), whose sum is σ = 36261120. Its totient is φ = 10360316.

The previous prime is 20720633. The next prime is 20720653. The reversal of 20720636 is 63602702.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20720633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2590076 + ... + 2590083.

It is an arithmetic number, because the mean of its divisors is an integer number (6043520).

Almost surely, 2^20720636 is an apocalyptic number.

It is an amenable number.

20720636 is a deficient number, since it is larger than the sum of its proper divisors (15540484).

20720636 is a wasteful number, since it uses less digits than its factorization.

20720636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5180163 (or 5180161 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 26.

The square root of 20720636 is about 4551.9925307496. The cubic root of 20720636 is about 274.6635488644.

The spelling of 20720636 in words is "twenty million, seven hundred twenty thousand, six hundred thirty-six".