20907631 has 2 divisors, whose sum is σ = 20907632. Its totient is φ = 20907630.

The previous prime is 20907571. The next prime is 20907643. The reversal of 20907631 is 13670902.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20907631 - 2¹⁷ = 20776559 is a prime.

It is a super-2 number, since 2×20907631² = 874258068064322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20907631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20901631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10453815 + 10453816.

It is an arithmetic number, because the mean of its divisors is an integer number (10453816).

Almost surely, 2^20907631 is an apocalyptic number.

20907631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20907631 is an equidigital number, since it uses as much as digits as its factorization.

20907631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 20907631 is about 4572.4863039707. The cubic root of 20907631 is about 275.4873166515.

The spelling of 20907631 in words is "twenty million, nine hundred seven thousand, six hundred thirty-one".