21615544116643 has 16 divisors (see below), whose sum is σ = 23304598096896. Its totient is φ = 19999916416480.

The previous prime is 21615544116623. The next prime is 21615544116653. The reversal of 21615544116643 is 34661144551612.

It is a cyclic number.

It is not a de Polignac number, because 21615544116643 - 2⁵ = 21615544116611 is a prime.

It is a super-2 number, since 2×21615544116643² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21615544116623) 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, 124788055 + ... + 124961152.

It is an arithmetic number, because the mean of its divisors is an integer number (1456537381056).

Almost surely, 2^{21615544116643} is an apocalyptic number.

21615544116643 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21615544116643 is a deficient number, since it is larger than the sum of its proper divisors (1689053980253).

21615544116643 is a wasteful number, since it uses less digits than its factorization.

21615544116643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249749354.

The product of its digits is 2073600, while the sum is 49.

The spelling of 21615544116643 in words is "twenty-one trillion, six hundred fifteen billion, five hundred forty-four million, one hundred sixteen thousand, six hundred forty-three".