20656680 has 64 divisors (see below), whose sum is σ = 67608000. Its totient is φ = 5007360.

The previous prime is 20656679. The next prime is 20656709. The reversal of 20656680 is 8665602.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6505 + ... + 9144.

It is an arithmetic number, because the mean of its divisors is an integer number (1056375).

Almost surely, 2^20656680 is an apocalyptic number.

20656680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20656680 is an abundant number, since it is smaller than the sum of its proper divisors (46951320).

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

20656680 is a wasteful number, since it uses less digits than its factorization.

20656680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15674 (or 15670 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 20656680 is about 4544.9620460461. The cubic root of 20656680 is about 274.3806668402.

The spelling of 20656680 in words is "twenty million, six hundred fifty-six thousand, six hundred eighty".