20957780 has 24 divisors (see below), whose sum is σ = 44634240. Its totient is φ = 8264480.

The previous prime is 20957777. The next prime is 20957819. The reversal of 20957780 is 8775902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5960 + ... + 8799.

It is an arithmetic number, because the mean of its divisors is an integer number (1859760).

Almost surely, 2^20957780 is an apocalyptic number.

20957780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20957780 is an abundant number, since it is smaller than the sum of its proper divisors (23676460).

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

20957780 is a wasteful number, since it uses less digits than its factorization.

20957780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14839 (or 14837 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 38.

The square root of 20957780 is about 4577.9667976079. The cubic root of 20957780 is about 275.7074018805.

The spelling of 20957780 in words is "twenty million, nine hundred fifty-seven thousand, seven hundred eighty".