21723413256 has 48 divisors (see below), whose sum is σ = 58844904300. Its totient is φ = 7239825792.

The previous prime is 21723413183. The next prime is 21723413287. The reversal of 21723413256 is 65231432712.

21723413256 is a `hidden beast` number, since 217 + 2 + 3 + 413 + 25 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 21677850756 + 45562500 = 147234^2 + 6750^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21723413256.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 424270 + ... + 472706.

Almost surely, 2^21723413256 is an apocalyptic number.

It is an amenable number.

21723413256 is an abundant number, since it is smaller than the sum of its proper divisors (37121491044).

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

21723413256 is a wasteful number, since it uses less digits than its factorization.

21723413256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54678 (or 54671 counting only the distinct ones).

The product of its digits is 60480, while the sum is 36.

Adding to 21723413256 its reverse (65231432712), we get a palindrome (86954845968).

The spelling of 21723413256 in words is "twenty-one billion, seven hundred twenty-three million, four hundred thirteen thousand, two hundred fifty-six".