21616657443 has 18 divisors (see below), whose sum is σ = 31298367516. Its totient is φ = 14376838392.

The previous prime is 21616657441. The next prime is 21616657453. The reversal of 21616657443 is 34475661612.

21616657443 is a `hidden beast` number, since 2 + 16 + 1 + 66 + 574 + 4 + 3 = 666.

It is not a de Polignac number, because 21616657443 - 2¹ = 21616657441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21616657441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 10086030 + ... + 10088172.

Almost surely, 2^21616657443 is an apocalyptic number.

21616657443 is a deficient number, since it is larger than the sum of its proper divisors (9681710073).

21616657443 is an frugal number, since it uses more digits than its factorization.

21616657443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4815 (or 2669 counting only the distinct ones).

The product of its digits is 725760, while the sum is 45.

The spelling of 21616657443 in words is "twenty-one billion, six hundred sixteen million, six hundred fifty-seven thousand, four hundred forty-three".