21611957523 has 16 divisors (see below), whose sum is σ = 32857999776. Its totient is φ = 12517332480.

The previous prime is 21611957491. The next prime is 21611957527. The reversal of 21611957523 is 32575911612.

It is a happy number.

It is not a de Polignac number, because 21611957523 - 2⁵ = 21611957491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21611957527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16297948 + ... + 16299273.

It is an arithmetic number, because the mean of its divisors is an integer number (2053624986).

Almost surely, 2^21611957523 is an apocalyptic number.

21611957523 is a deficient number, since it is larger than the sum of its proper divisors (11246042253).

21611957523 is a wasteful number, since it uses less digits than its factorization.

21611957523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32597254.

The product of its digits is 113400, while the sum is 42.

The spelling of 21611957523 in words is "twenty-one billion, six hundred eleven million, nine hundred fifty-seven thousand, five hundred twenty-three".