21579707 has 2 divisors, whose sum is σ = 21579708. Its totient is φ = 21579706.

The previous prime is 21579673. The next prime is 21579709. The reversal of 21579707 is 70797512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21579707 - 2⁶ = 21579643 is a prime.

Together with 21579709, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21579709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10789853 + 10789854.

It is an arithmetic number, because the mean of its divisors is an integer number (10789854).

Almost surely, 2^21579707 is an apocalyptic number.

21579707 is a deficient number, since it is larger than the sum of its proper divisors (1).

21579707 is an equidigital number, since it uses as much as digits as its factorization.

21579707 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30870, while the sum is 38.

The square root of 21579707 is about 4645.3963232430. The cubic root of 21579707 is about 278.4080880954.

The spelling of 21579707 in words is "twenty-one million, five hundred seventy-nine thousand, seven hundred seven".