21573934461 has 6 divisors (see below), whose sum is σ = 31162349790. Its totient is φ = 14382622968.

The previous prime is 21573934453. The next prime is 21573934483. The reversal of 21573934461 is 16443937512.

21573934461 is a `hidden beast` number, since 2 + 1 + 573 + 9 + 34 + 46 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21146685561 + 427248900 = 145419^2 + 20670^2 .

It is not a de Polignac number, because 21573934461 - 2³ = 21573934453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573934061) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1198551906 + ... + 1198551923.

It is an arithmetic number, because the mean of its divisors is an integer number (5193724965).

Almost surely, 2^21573934461 is an apocalyptic number.

It is an amenable number.

21573934461 is a deficient number, since it is larger than the sum of its proper divisors (9588415329).

21573934461 is a wasteful number, since it uses less digits than its factorization.

21573934461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2397103835 (or 2397103832 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The spelling of 21573934461 in words is "twenty-one billion, five hundred seventy-three million, nine hundred thirty-four thousand, four hundred sixty-one".