20639772 has 30 divisors (see below), whose sum is σ = 53957288. Its totient is φ = 6879816.

The previous prime is 20639767. The next prime is 20639779. The reversal of 20639772 is 27793602.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20639779) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 31528 + ... + 32175.

Almost surely, 2^20639772 is an apocalyptic number.

It is an amenable number.

20639772 is an abundant number, since it is smaller than the sum of its proper divisors (33317516).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20639772 is a wasteful number, since it uses less digits than its factorization.

20639772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63719 (or 63708 counting only the distinct ones).

The product of its (nonzero) digits is 31752, while the sum is 36.

The square root of 20639772 is about 4543.1015837201. The cubic root of 20639772 is about 274.3057839667.

The spelling of 20639772 in words is "twenty million, six hundred thirty-nine thousand, seven hundred seventy-two".