21615834315855 has 32 divisors (see below), whose sum is σ = 37367067032064. Its totient is φ = 10606978152576.

The previous prime is 21615834315841. The next prime is 21615834315979. The reversal of 21615834315855 is 55851343851612.

It is not a de Polignac number, because 21615834315855 - 2¹⁰ = 21615834314831 is a prime.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21615834315795 and 21615834315804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 180478299 + ... + 180598028.

It is an arithmetic number, because the mean of its divisors is an integer number (1167720844752).

Almost surely, 2^{21615834315855} is an apocalyptic number.

21615834315855 is a deficient number, since it is larger than the sum of its proper divisors (15751232716209).

21615834315855 is a wasteful number, since it uses less digits than its factorization.

21615834315855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361076655.

The product of its digits is 17280000, while the sum is 57.

The spelling of 21615834315855 in words is "twenty-one trillion, six hundred fifteen billion, eight hundred thirty-four million, three hundred fifteen thousand, eight hundred fifty-five".