21718327 has 2 divisors, whose sum is σ = 21718328. Its totient is φ = 21718326.

The previous prime is 21718267. The next prime is 21718351. The reversal of 21718327 is 72381712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21718327 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21718427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10859163 + 10859164.

It is an arithmetic number, because the mean of its divisors is an integer number (10859164).

Almost surely, 2^21718327 is an apocalyptic number.

21718327 is a deficient number, since it is larger than the sum of its proper divisors (1).

21718327 is an equidigital number, since it uses as much as digits as its factorization.

21718327 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 31.

The square root of 21718327 is about 4660.2925873812. The cubic root of 21718327 is about 279.0029461455.

The spelling of 21718327 in words is "twenty-one million, seven hundred eighteen thousand, three hundred twenty-seven".