21253557796 has 9 divisors (see below), whose sum is σ = 37194236401. Its totient is φ = 10626633112.

The previous prime is 21253557697. The next prime is 21253557803. The reversal of 21253557796 is 69775535212.

The square root of 21253557796 is 145786.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 362902500 + 20890655296 = 19050^2 + 144536^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 255126 + ... + 328018.

Almost surely, 2^21253557796 is an apocalyptic number.

21253557796 is the 145786-th square number.

It is an amenable number.

21253557796 is a deficient number, since it is larger than the sum of its proper divisors (15940678605).

21253557796 is an frugal number, since it uses more digits than its factorization.

21253557796 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145790 (or 72895 counting only the distinct ones).

The product of its digits is 3969000, while the sum is 52.

The spelling of 21253557796 in words is "twenty-one billion, two hundred fifty-three million, five hundred fifty-seven thousand, seven hundred ninety-six".