20638734631 has 2 divisors, whose sum is σ = 20638734632. Its totient is φ = 20638734630.

The previous prime is 20638734619. The next prime is 20638734661. The reversal of 20638734631 is 13643783602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20638734631 - 2²¹ = 20636637479 is a prime.

It is a super-2 number, since 2×20638734631² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20638734661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10319367315 + 10319367316.

It is an arithmetic number, because the mean of its divisors is an integer number (10319367316).

Almost surely, 2^20638734631 is an apocalyptic number.

20638734631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20638734631 is an equidigital number, since it uses as much as digits as its factorization.

20638734631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 435456, while the sum is 43.

The spelling of 20638734631 in words is "twenty billion, six hundred thirty-eight million, seven hundred thirty-four thousand, six hundred thirty-one".