20571057 has 32 divisors (see below), whose sum is σ = 33196800. Its totient is φ = 12514176.

The previous prime is 20571041. The next prime is 20571119. The reversal of 20571057 is 75017502.

It is not a de Polignac number, because 20571057 - 2⁴ = 20571041 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 20571057.

It is not an unprimeable number, because it can be changed into a prime (20571017) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35869 + ... + 36437.

It is an arithmetic number, because the mean of its divisors is an integer number (1037400).

Almost surely, 2^20571057 is an apocalyptic number.

20571057 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

20571057 is a deficient number, since it is larger than the sum of its proper divisors (12625743).

20571057 is a wasteful number, since it uses less digits than its factorization.

20571057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 694 (or 688 counting only the distinct ones).

The product of its (nonzero) digits is 2450, while the sum is 27.

The square root of 20571057 is about 4535.5327140260. The cubic root of 20571057 is about 274.0010345033.

Adding to 20571057 its reverse (75017502), we get a palindrome (95588559).

The spelling of 20571057 in words is "twenty million, five hundred seventy-one thousand, fifty-seven".