20904417 has 6 divisors (see below), whose sum is σ = 30195282. Its totient is φ = 13936272.

The previous prime is 20904413. The next prime is 20904421. The reversal of 20904417 is 71440902.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20904413) and next prime (20904421).

It can be written as a sum of positive squares in only one way, i.e., 12047841 + 8856576 = 3471^2 + 2976^2 .

It is not a de Polignac number, because 20904417 - 2² = 20904413 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20904413) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1161348 + ... + 1161365.

It is an arithmetic number, because the mean of its divisors is an integer number (5032547).

Almost surely, 2^20904417 is an apocalyptic number.

It is an amenable number.

20904417 is a deficient number, since it is larger than the sum of its proper divisors (9290865).

20904417 is a wasteful number, since it uses less digits than its factorization.

20904417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2322719 (or 2322716 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 20904417 is about 4572.1348405313. The cubic root of 20904417 is about 275.4731996112.

It can be divided in two parts, 20904 and 417, that added together give a triangular number (21321 = T₂₀₆).

The spelling of 20904417 in words is "twenty million, nine hundred four thousand, four hundred seventeen".