21957597748 has 6 divisors (see below), whose sum is σ = 38425796066. Its totient is φ = 10978798872.

The previous prime is 21957597743. The next prime is 21957597763. The reversal of 21957597748 is 84779575912.

It can be written as a sum of positive squares in only one way, i.e., 13703511844 + 8254085904 = 117062^2 + 90852^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21957597748.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21957597743) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2744699715 + ... + 2744699722.

Almost surely, 2^21957597748 is an apocalyptic number.

It is an amenable number.

21957597748 is a deficient number, since it is larger than the sum of its proper divisors (16468198318).

21957597748 is a wasteful number, since it uses less digits than its factorization.

21957597748 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5489399441 (or 5489399439 counting only the distinct ones).

The product of its digits is 44452800, while the sum is 64.

The spelling of 21957597748 in words is "twenty-one billion, nine hundred fifty-seven million, five hundred ninety-seven thousand, seven hundred forty-eight".