21111120631 has 2 divisors, whose sum is σ = 21111120632. Its totient is φ = 21111120630.

The previous prime is 21111120623. The next prime is 21111120661. The reversal of 21111120631 is 13602111112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21111120631 - 2³ = 21111120623 is a prime.

It is a super-2 number, since 2×21111120631² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21111120599 and 21111120608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21111120601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555560315 + 10555560316.

It is an arithmetic number, because the mean of its divisors is an integer number (10555560316).

Almost surely, 2^21111120631 is an apocalyptic number.

21111120631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111120631 is an equidigital number, since it uses as much as digits as its factorization.

21111120631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 19.

Adding to 21111120631 its reverse (13602111112), we get a palindrome (34713231743).

The spelling of 21111120631 in words is "twenty-one billion, one hundred eleven million, one hundred twenty thousand, six hundred thirty-one".