21724607 has 2 divisors, whose sum is σ = 21724608. Its totient is φ = 21724606.

The previous prime is 21724553. The next prime is 21724609. The reversal of 21724607 is 70642712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21724607 - 2¹² = 21720511 is a prime.

Together with 21724609, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21724607.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21724609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862303 + 10862304.

It is an arithmetic number, because the mean of its divisors is an integer number (10862304).

Almost surely, 2^21724607 is an apocalyptic number.

21724607 is a deficient number, since it is larger than the sum of its proper divisors (1).

21724607 is an equidigital number, since it uses as much as digits as its factorization.

21724607 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 21724607 is about 4660.9663161194. The cubic root of 21724607 is about 279.0298354120.

The spelling of 21724607 in words is "twenty-one million, seven hundred twenty-four thousand, six hundred seven".