20404945 has 24 divisors (see below), whose sum is σ = 27554688. Its totient is φ = 14385600.

The previous prime is 20404939. The next prime is 20404949. The reversal of 20404945 is 54940402.

It is not a de Polignac number, because 20404945 - 2⁷ = 20404817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20404949) 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, 75160 + ... + 75430.

It is an arithmetic number, because the mean of its divisors is an integer number (1148112).

Almost surely, 2^20404945 is an apocalyptic number.

It is an amenable number.

20404945 is a deficient number, since it is larger than the sum of its proper divisors (7149743).

20404945 is a wasteful number, since it uses less digits than its factorization.

20404945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361 (or 324 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 20404945 is about 4517.1833037857. The cubic root of 20404945 is about 273.2615177512.

The spelling of 20404945 in words is "twenty million, four hundred four thousand, nine hundred forty-five".