21689627 has 2 divisors, whose sum is σ = 21689628. Its totient is φ = 21689626.

The previous prime is 21689617. The next prime is 21689669. The reversal of 21689627 is 72698612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21689627 - 2⁴ = 21689611 is a prime.

It is not a weakly prime, because it can be changed into another prime (21689617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10844813 + 10844814.

It is an arithmetic number, because the mean of its divisors is an integer number (10844814).

Almost surely, 2^21689627 is an apocalyptic number.

21689627 is a deficient number, since it is larger than the sum of its proper divisors (1).

21689627 is an equidigital number, since it uses as much as digits as its factorization.

21689627 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 41.

The square root of 21689627 is about 4657.2123636356. The cubic root of 21689627 is about 278.8799944666.

The spelling of 21689627 in words is "twenty-one million, six hundred eighty-nine thousand, six hundred twenty-seven".