20813680 has 20 divisors (see below), whose sum is σ = 48391992. Its totient is φ = 8325440.

The previous prime is 20813669. The next prime is 20813693. The reversal of 20813680 is 8631802.

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, 130006 + ... + 130165.

Almost surely, 2^20813680 is an apocalyptic number.

20813680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20813680 is an abundant number, since it is smaller than the sum of its proper divisors (27578312).

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

20813680 is a wasteful number, since it uses less digits than its factorization.

20813680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260184 (or 260178 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 20813680 is about 4562.2012230940. The cubic root of 20813680 is about 275.0740516830.

The spelling of 20813680 in words is "twenty million, eight hundred thirteen thousand, six hundred eighty".