20909475 has 24 divisors (see below), whose sum is σ = 38412720. Its totient is φ = 11151360.

The previous prime is 20909453. The next prime is 20909479. The reversal of 20909475 is 57490902.

It is not a de Polignac number, because 20909475 - 2⁷ = 20909347 is a prime.

It is a super-2 number, since 2×20909475² = 874412289551250, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20909479) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14814 + ... + 16163.

It is an arithmetic number, because the mean of its divisors is an integer number (1600530).

Almost surely, 2^20909475 is an apocalyptic number.

20909475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20909475 is a deficient number, since it is larger than the sum of its proper divisors (17503245).

20909475 is a wasteful number, since it uses less digits than its factorization.

20909475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30996 (or 30985 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 20909475 is about 4572.6879403694. The cubic root of 20909475 is about 275.4954155075.

The spelling of 20909475 in words is "twenty million, nine hundred nine thousand, four hundred seventy-five".