20925491 has 4 divisors (see below), whose sum is σ = 20940192. Its totient is φ = 20910792.

The previous prime is 20925467. The next prime is 20925533. The reversal of 20925491 is 19452902.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20925491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20922491) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4955 + ... + 8148.

It is an arithmetic number, because the mean of its divisors is an integer number (5235048).

Almost surely, 2^20925491 is an apocalyptic number.

20925491 is a deficient number, since it is larger than the sum of its proper divisors (14701).

20925491 is a wasteful number, since it uses less digits than its factorization.

20925491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14700.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 20925491 is about 4574.4388726925. The cubic root of 20925491 is about 275.5657378293.

The spelling of 20925491 in words is "twenty million, nine hundred twenty-five thousand, four hundred ninety-one".