20908231 has 2 divisors, whose sum is σ = 20908232. Its totient is φ = 20908230.

The previous prime is 20908211. The next prime is 20908247. The reversal of 20908231 is 13280902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20908231 - 2⁷ = 20908103 is a prime.

It is a super-2 number, since 2×20908231² = 874308247098722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20908196 and 20908205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20908211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10454115 + 10454116.

It is an arithmetic number, because the mean of its divisors is an integer number (10454116).

Almost surely, 2^20908231 is an apocalyptic number.

20908231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20908231 is an equidigital number, since it uses as much as digits as its factorization.

20908231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 20908231 is about 4572.5519133193. The cubic root of 20908231 is about 275.4899519064.

The spelling of 20908231 in words is "twenty million, nine hundred eight thousand, two hundred thirty-one".