20656631 has 2 divisors, whose sum is σ = 20656632. Its totient is φ = 20656630.

The previous prime is 20656627. The next prime is 20656639. The reversal of 20656631 is 13665602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20656631 - 2² = 20656627 is a prime.

It is a super-2 number, since 2×20656631² = 853392808540322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20656594 and 20656603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20656639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10328315 + 10328316.

It is an arithmetic number, because the mean of its divisors is an integer number (10328316).

Almost surely, 2^20656631 is an apocalyptic number.

20656631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20656631 is an equidigital number, since it uses as much as digits as its factorization.

20656631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 20656631 is about 4544.9566554589. The cubic root of 20656631 is about 274.3804498860.

The spelling of 20656631 in words is "twenty million, six hundred fifty-six thousand, six hundred thirty-one".