21613121623 has 12 divisors (see below), whose sum is σ = 22819022688. Its totient is φ = 20467961280.

The previous prime is 21613121611. The next prime is 21613121657. The reversal of 21613121623 is 32612131612.

It is not a de Polignac number, because 21613121623 - 2²¹ = 21611024471 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21613121591 and 21613121600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21613121323) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1117090 + ... + 1136272.

It is an arithmetic number, because the mean of its divisors is an integer number (1901585224).

Almost surely, 2^21613121623 is an apocalyptic number.

21613121623 is a deficient number, since it is larger than the sum of its proper divisors (1205901065).

21613121623 is a wasteful number, since it uses less digits than its factorization.

21613121623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22342 (or 22323 counting only the distinct ones).

The product of its digits is 2592, while the sum is 28.

The spelling of 21613121623 in words is "twenty-one billion, six hundred thirteen million, one hundred twenty-one thousand, six hundred twenty-three".