20651820 has 48 divisors (see below), whose sum is σ = 66087168. Its totient is φ = 4720320.

The previous prime is 20651819. The next prime is 20651831. The reversal of 20651820 is 2815602.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24166 + ... + 25005.

It is an arithmetic number, because the mean of its divisors is an integer number (1376816).

Almost surely, 2^20651820 is an apocalyptic number.

20651820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20651820 is an abundant number, since it is smaller than the sum of its proper divisors (45435348).

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

20651820 is a wasteful number, since it uses less digits than its factorization.

20651820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49190 (or 49188 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 20651820 is about 4544.4273566644. The cubic root of 20651820 is about 274.3591468503.

The spelling of 20651820 in words is "twenty million, six hundred fifty-one thousand, eight hundred twenty".