20957481 has 16 divisors (see below), whose sum is σ = 32875200. Its totient is φ = 13149504.

The previous prime is 20957479. The next prime is 20957491. The reversal of 20957481 is 18475902.

20957481 is a `hidden beast` number, since 2 + 0 + 9 + 574 + 81 = 666.

It is not a de Polignac number, because 20957481 - 2¹ = 20957479 is a prime.

It is a super-2 number, since 2×20957481² = 878432019730722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20957491) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22371 + ... + 23288.

It is an arithmetic number, because the mean of its divisors is an integer number (2054700).

Almost surely, 2^20957481 is an apocalyptic number.

It is an amenable number.

20957481 is a deficient number, since it is larger than the sum of its proper divisors (11917719).

20957481 is a wasteful number, since it uses less digits than its factorization.

20957481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45685 (or 45679 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 20957481 is about 4577.9341410728. The cubic root of 20957481 is about 275.7060907221.

The spelling of 20957481 in words is "twenty million, nine hundred fifty-seven thousand, four hundred eighty-one".