21315079 has 2 divisors, whose sum is σ = 21315080. Its totient is φ = 21315078.

The previous prime is 21315067. The next prime is 21315083. The reversal of 21315079 is 97051312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21315079 - 2⁹ = 21314567 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 (21312079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657539 + 10657540.

It is an arithmetic number, because the mean of its divisors is an integer number (10657540).

Almost surely, 2^21315079 is an apocalyptic number.

21315079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315079 is an equidigital number, since it uses as much as digits as its factorization.

21315079 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21315079 is about 4616.8256410655. The cubic root of 21315079 is about 277.2653818679.

The spelling of 21315079 in words is "twenty-one million, three hundred fifteen thousand, seventy-nine".