20920631 has 2 divisors, whose sum is σ = 20920632. Its totient is φ = 20920630.

The previous prime is 20920589. The next prime is 20920649. The reversal of 20920631 is 13602902.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20920631 is a prime.

It is a super-2 number, since 2×20920631² = 875345602876322, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1325255 and since 20920631 and 1325255 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 20920597 and 20920606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20920331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10460315 + 10460316.

It is an arithmetic number, because the mean of its divisors is an integer number (10460316).

Almost surely, 2^20920631 is an apocalyptic number.

20920631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20920631 is an equidigital number, since it uses as much as digits as its factorization.

20920631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 20920631 is about 4573.9076291504. The cubic root of 20920631 is about 275.5444025564.

The spelling of 20920631 in words is "twenty million, nine hundred twenty thousand, six hundred thirty-one".