21365699 has 2 divisors, whose sum is σ = 21365700. Its totient is φ = 21365698.

The previous prime is 21365657. The next prime is 21365723. The reversal of 21365699 is 99656312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21365699 - 2²⁴ = 4588483 is a prime.

It is not a weakly prime, because it can be changed into another prime (21365609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682849 + 10682850.

It is an arithmetic number, because the mean of its divisors is an integer number (10682850).

Almost surely, 2^21365699 is an apocalyptic number.

21365699 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365699 is an equidigital number, since it uses as much as digits as its factorization.

21365699 is an evil number, because the sum of its binary digits is even.

The product of its digits is 87480, while the sum is 41.

The square root of 21365699 is about 4622.3045118209. The cubic root of 21365699 is about 277.4846957445.

The spelling of 21365699 in words is "twenty-one million, three hundred sixty-five thousand, six hundred ninety-nine".