21076631 has 2 divisors, whose sum is σ = 21076632. Its totient is φ = 21076630.

The previous prime is 21076619. The next prime is 21076637. The reversal of 21076631 is 13667012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21076631 is a prime.

It is a super-2 number, since 2×21076631² = 888448748620322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21076631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21076637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10538315 + 10538316.

It is an arithmetic number, because the mean of its divisors is an integer number (10538316).

Almost surely, 2^21076631 is an apocalyptic number.

21076631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21076631 is an equidigital number, since it uses as much as digits as its factorization.

21076631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21076631 is about 4590.9292087768. The cubic root of 21076631 is about 276.2275961711.

The spelling of 21076631 in words is "twenty-one million, seventy-six thousand, six hundred thirty-one".