21615566103487 has 2 divisors, whose sum is σ = 21615566103488. Its totient is φ = 21615566103486.

The previous prime is 21615566103479. The next prime is 21615566103499. The reversal of 21615566103487 is 78430166551612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21615566103487 - 2³ = 21615566103479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21615566133487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10807783051743 + 10807783051744.

It is an arithmetic number, because the mean of its divisors is an integer number (10807783051744).

Almost surely, 2^{21615566103487} is an apocalyptic number.

21615566103487 is a deficient number, since it is larger than the sum of its proper divisors (1).

21615566103487 is an equidigital number, since it uses as much as digits as its factorization.

21615566103487 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7257600, while the sum is 55.

The spelling of 21615566103487 in words is "twenty-one trillion, six hundred fifteen billion, five hundred sixty-six million, one hundred three thousand, four hundred eighty-seven".