21276631 has 2 divisors, whose sum is σ = 21276632. Its totient is φ = 21276630.

The previous prime is 21276623. The next prime is 21276643. The reversal of 21276631 is 13667212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21276631 - 2³ = 21276623 is a prime.

It is a super-2 number, since 2×21276631² = 905390053420322, 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 21276631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21276611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638315 + 10638316.

It is an arithmetic number, because the mean of its divisors is an integer number (10638316).

Almost surely, 2^21276631 is an apocalyptic number.

21276631 is a deficient number, since it is larger than the sum of its proper divisors (1).

21276631 is an equidigital number, since it uses as much as digits as its factorization.

21276631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 21276631 is about 4612.6598617284. The cubic root of 21276631 is about 277.0985717036.

The spelling of 21276631 in words is "twenty-one million, two hundred seventy-six thousand, six hundred thirty-one".