21276491 has 2 divisors, whose sum is σ = 21276492. Its totient is φ = 21276490.

The previous prime is 21276487. The next prime is 21276547. The reversal of 21276491 is 19467212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21276491 - 2² = 21276487 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21276461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638245 + 10638246.

It is an arithmetic number, because the mean of its divisors is an integer number (10638246).

Almost surely, 2^21276491 is an apocalyptic number.

21276491 is a deficient number, since it is larger than the sum of its proper divisors (1).

21276491 is an equidigital number, since it uses as much as digits as its factorization.

21276491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 32.

The square root of 21276491 is about 4612.6446860776. The cubic root of 21276491 is about 277.0979639337.

The spelling of 21276491 in words is "twenty-one million, two hundred seventy-six thousand, four hundred ninety-one".