21615611402653 has 16 divisors (see below), whose sum is σ = 22154627886336. Its totient is φ = 21078272517120.

The previous prime is 21615611402543. The next prime is 21615611402849. The reversal of 21615611402653 is 35620411651612.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21615611402653 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21615611402953) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 69385948 + ... + 69696778.

It is an arithmetic number, because the mean of its divisors is an integer number (1384664242896).

Almost surely, 2^{21615611402653} is an apocalyptic number.

It is an amenable number.

21615611402653 is a deficient number, since it is larger than the sum of its proper divisors (539016483683).

21615611402653 is a wasteful number, since it uses less digits than its factorization.

21615611402653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313524.

The product of its (nonzero) digits is 259200, while the sum is 43.

The spelling of 21615611402653 in words is "twenty-one trillion, six hundred fifteen billion, six hundred eleven million, four hundred two thousand, six hundred fifty-three".