21315599 has 2 divisors, whose sum is σ = 21315600. Its totient is φ = 21315598.

The previous prime is 21315583. The next prime is 21315607. The reversal of 21315599 is 99551312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21315599 - 2⁴ = 21315583 is a prime.

It is a Chen prime.

It is a zygodrome in base 3.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21315509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657799 + 10657800.

It is an arithmetic number, because the mean of its divisors is an integer number (10657800).

Almost surely, 2^21315599 is an apocalyptic number.

21315599 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315599 is an equidigital number, since it uses as much as digits as its factorization.

21315599 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12150, while the sum is 35.

The square root of 21315599 is about 4616.8819564724. The cubic root of 21315599 is about 277.2676365601.

The spelling of 21315599 in words is "twenty-one million, three hundred fifteen thousand, five hundred ninety-nine".