20557705 has 16 divisors (see below), whose sum is σ = 28771200. Its totient is φ = 14095536.

The previous prime is 20557697. The next prime is 20557711. The reversal of 20557705 is 50775502.

It is not a de Polignac number, because 20557705 - 2³ = 20557697 is a prime.

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, 4279 + ... + 7708.

It is an arithmetic number, because the mean of its divisors is an integer number (1798200).

Almost surely, 2^20557705 is an apocalyptic number.

It is an amenable number.

20557705 is a deficient number, since it is larger than the sum of its proper divisors (8213495).

20557705 is an equidigital number, since it uses as much as digits as its factorization.

20557705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12013 (or 11999 counting only the distinct ones).

The product of its (nonzero) digits is 12250, while the sum is 31.

The square root of 20557705 is about 4534.0605421631. The cubic root of 20557705 is about 273.9417399708.

The spelling of 20557705 in words is "twenty million, five hundred fifty-seven thousand, seven hundred five".