21615566103479 has 2 divisors, whose sum is σ = 21615566103480. Its totient is φ = 21615566103478.

The previous prime is 21615566103431. The next prime is 21615566103487. The reversal of 21615566103479 is 97430166551612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21615566103479 - 2²⁴ = 21615549326263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21615566103499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10807783051739 + 10807783051740.

It is an arithmetic number, because the mean of its divisors is an integer number (10807783051740).

Almost surely, 2^{21615566103479} is an apocalyptic number.

21615566103479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21615566103479 is an equidigital number, since it uses as much as digits as its factorization.

21615566103479 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8164800, while the sum is 56.

The spelling of 21615566103479 in words is "twenty-one trillion, six hundred fifteen billion, five hundred sixty-six million, one hundred three thousand, four hundred seventy-nine".