20902905 has 24 divisors (see below), whose sum is σ = 36411648. Its totient is φ = 11092896.

The previous prime is 20902901. The next prime is 20902943. The reversal of 20902905 is 50920902.

It is not a de Polignac number, because 20902905 - 2² = 20902901 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20902901) 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, 8994 + ... + 11076.

It is an arithmetic number, because the mean of its divisors is an integer number (1517152).

Almost surely, 2^20902905 is an apocalyptic number.

It is an amenable number.

20902905 is a deficient number, since it is larger than the sum of its proper divisors (15508743).

20902905 is a wasteful number, since it uses less digits than its factorization.

20902905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2317 (or 2314 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 20902905 is about 4571.9694880872. The cubic root of 20902905 is about 275.4665578647.

The spelling of 20902905 in words is "twenty million, nine hundred two thousand, nine hundred five".