20557975 has 12 divisors (see below), whose sum is σ = 26600976. Its totient is φ = 15730880.

The previous prime is 20557973. The next prime is 20557993. The reversal of 20557975 is 57975502.

It is not a de Polignac number, because 20557975 - 2¹ = 20557973 is a prime.

It is a super-2 number, since 2×20557975² = 845260672201250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20557973) 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 11 ways as a sum of consecutive naturals, for example, 17302 + ... + 18451.

It is an arithmetic number, because the mean of its divisors is an integer number (2216748).

Almost surely, 2^20557975 is an apocalyptic number.

20557975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20557975 is a deficient number, since it is larger than the sum of its proper divisors (6043001).

20557975 is a wasteful number, since it uses less digits than its factorization.

20557975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35786 (or 35781 counting only the distinct ones).

The product of its (nonzero) digits is 110250, while the sum is 40.

The square root of 20557975 is about 4534.0903167008. The cubic root of 20557975 is about 273.9429392607.

The spelling of 20557975 in words is "twenty million, five hundred fifty-seven thousand, nine hundred seventy-five".