21161320124 has 18 divisors (see below), whose sum is σ = 43078402080. Its totient is φ = 9069137112.

The previous prime is 21161320111. The next prime is 21161320153. The reversal of 21161320124 is 42102316112.

It is a self number, because there is not a number n which added to its sum of digits gives 21161320124.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53982764 + ... + 53983155.

It is an arithmetic number, because the mean of its divisors is an integer number (2393244560).

Almost surely, 2^21161320124 is an apocalyptic number.

It is an amenable number.

21161320124 is an abundant number, since it is smaller than the sum of its proper divisors (21917081956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21161320124 is a wasteful number, since it uses less digits than its factorization.

21161320124 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107965937 (or 107965928 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 23.

Adding to 21161320124 its reverse (42102316112), we get a palindrome (63263636236).

The spelling of 21161320124 in words is "twenty-one billion, one hundred sixty-one million, three hundred twenty thousand, one hundred twenty-four".