28371696721 has 9 divisors (see below), whose sum is σ = 28561435483. Its totient is φ = 28183213480.

The previous prime is 28371696719. The next prime is 28371696757. The reversal of 28371696721 is 12769617382.

The square root of 28371696721 is 168439.

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., 17593104321 + 10778592400 = 132639^2 + 103820^2 .

It is not a de Polignac number, because 28371696721 - 2¹ = 28371696719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28371696791) 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, 30150111 + ... + 30151051.

Almost surely, 2^28371696721 is an apocalyptic number.

28371696721 is the 168439-th square number.

28371696721 is the 84220-th centered octagonal number.

It is an amenable number.

28371696721 is a deficient number, since it is larger than the sum of its proper divisors (189738762).

28371696721 is an frugal number, since it uses more digits than its factorization.

28371696721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240 (or 1120 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 52.

The spelling of 28371696721 in words is "twenty-eight billion, three hundred seventy-one million, six hundred ninety-six thousand, seven hundred twenty-one".