20717680 has 20 divisors (see below), whose sum is σ = 48168792. Its totient is φ = 8287040.

The previous prime is 20717677. The next prime is 20717693. The reversal of 20717680 is 8671702.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 129406 + ... + 129565.

Almost surely, 2^20717680 is an apocalyptic number.

20717680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20717680 is an abundant number, since it is smaller than the sum of its proper divisors (27451112).

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

20717680 is a wasteful number, since it uses less digits than its factorization.

20717680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258984 (or 258978 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 20717680 is about 4551.6678261929. The cubic root of 20717680 is about 274.6504871022.

The spelling of 20717680 in words is "twenty million, seven hundred seventeen thousand, six hundred eighty".