20646631 has 2 divisors, whose sum is σ = 20646632. Its totient is φ = 20646630.

The previous prime is 20646611. The next prime is 20646667. The reversal of 20646631 is 13664602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20646631 - 2⁷ = 20646503 is a prime.

It is a super-2 number, since 2×20646631² = 852566743300322, 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 20646631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20646611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10323315 + 10323316.

It is an arithmetic number, because the mean of its divisors is an integer number (10323316).

Almost surely, 2^20646631 is an apocalyptic number.

20646631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20646631 is an equidigital number, since it uses as much as digits as its factorization.

20646631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 20646631 is about 4543.8564017803. The cubic root of 20646631 is about 274.3361663275.

The spelling of 20646631 in words is "twenty million, six hundred forty-six thousand, six hundred thirty-one".