21601553356115 has 24 divisors (see below), whose sum is σ = 27557189921520. Its totient is φ = 16249716659264.

The previous prime is 21601553356063. The next prime is 21601553356129. The reversal of 21601553356115 is 51165335510612.

It is not a de Polignac number, because 21601553356115 - 2³⁶ = 21532833879379 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69055292 + ... + 69367401.

It is an arithmetic number, because the mean of its divisors is an integer number (1148216246730).

Almost surely, 2^{21601553356115} is an apocalyptic number.

21601553356115 is a deficient number, since it is larger than the sum of its proper divisors (5955636565405).

21601553356115 is a wasteful number, since it uses less digits than its factorization.

21601553356115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138422803 (or 138422780 counting only the distinct ones).

The product of its (nonzero) digits is 405000, while the sum is 44.

Adding to 21601553356115 its reverse (51165335510612), we get a palindrome (72766888866727).

The spelling of 21601553356115 in words is "twenty-one trillion, six hundred one billion, five hundred fifty-three million, three hundred fifty-six thousand, one hundred fifteen".