20755657 has 16 divisors (see below), whose sum is σ = 24917760. Its totient is φ = 17079552.

The previous prime is 20755649. The next prime is 20755661. The reversal of 20755657 is 75655702.

It is a cyclic number.

It is not a de Polignac number, because 20755657 - 2³ = 20755649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20755057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1728 + ... + 6670.

It is an arithmetic number, because the mean of its divisors is an integer number (1557360).

Almost surely, 2^20755657 is an apocalyptic number.

It is an amenable number.

20755657 is a deficient number, since it is larger than the sum of its proper divisors (4162103).

20755657 is a wasteful number, since it uses less digits than its factorization.

20755657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4992.

The product of its (nonzero) digits is 73500, while the sum is 37.

The square root of 20755657 is about 4555.8376836757. The cubic root of 20755657 is about 274.8182027088.

It can be divided in two parts, 20755 and 657, that added together give a palindrome (21412).

The spelling of 20755657 in words is "twenty million, seven hundred fifty-five thousand, six hundred fifty-seven".