20925909 has 12 divisors (see below), whose sum is σ = 30678336. Its totient is φ = 13741992.

The previous prime is 20925881. The next prime is 20925911. The reversal of 20925909 is 90952902.

It is not a de Polignac number, because 20925909 - 2⁷ = 20925781 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20925209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16749 + ... + 17954.

It is an arithmetic number, because the mean of its divisors is an integer number (2556528).

Almost surely, 2^20925909 is an apocalyptic number.

It is an amenable number.

20925909 is a deficient number, since it is larger than the sum of its proper divisors (9752427).

20925909 is a wasteful number, since it uses less digits than its factorization.

20925909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34776 (or 34773 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 20925909 is about 4574.4845611282. The cubic root of 20925909 is about 275.5675726840.

It can be divided in two parts, 2092 and 5909, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 20925909 in words is "twenty million, nine hundred twenty-five thousand, nine hundred nine".