21272805904 has 45 divisors (see below), whose sum is σ = 47954420397. Its totient is φ = 9115166592.

The previous prime is 21272805893. The next prime is 21272805907. The reversal of 21272805904 is 40950827212.

The square root of 21272805904 is 145852.

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., 20866380304 + 406425600 = 144452^2 + 20160^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21272805907) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4081252 + ... + 4086460.

Almost surely, 2^21272805904 is an apocalyptic number.

21272805904 is the 145852-nd square number.

It is an amenable number.

21272805904 is an abundant number, since it is smaller than the sum of its proper divisors (26681614493).

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

21272805904 is an frugal number, since it uses more digits than its factorization.

21272805904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10440 (or 5218 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The spelling of 21272805904 in words is "twenty-one billion, two hundred seventy-two million, eight hundred five thousand, nine hundred four".