21615566103623 has 2 divisors, whose sum is σ = 21615566103624. Its totient is φ = 21615566103622.

The previous prime is 21615566103601. The next prime is 21615566103643. The reversal of 21615566103623 is 32630166551612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21615566103623 - 2⁶ = 21615566103559 is a prime.

It is a super-2 number, since 2×21615566103623² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21615566103643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10807783051811 + 10807783051812.

It is an arithmetic number, because the mean of its divisors is an integer number (10807783051812).

Almost surely, 2^{21615566103623} is an apocalyptic number.

21615566103623 is a deficient number, since it is larger than the sum of its proper divisors (1).

21615566103623 is an equidigital number, since it uses as much as digits as its factorization.

21615566103623 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1166400, while the sum is 47.

The spelling of 21615566103623 in words is "twenty-one trillion, six hundred fifteen billion, five hundred sixty-six million, one hundred three thousand, six hundred twenty-three".