28750932721 has 9 divisors (see below), whose sum is σ = 33446343321. Its totient is φ = 24642639252.

The previous prime is 28750932709. The next prime is 28750932767. The reversal of 28750932721 is 12723905782.

The square root of 28750932721 is 169561.

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

It is a de Polignac number, because none of the positive numbers 2^k-28750932721 is a prime.

It is a super-2 number, since 2×28750932721² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28750902721) 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, 1174816 + ... + 1199038.

It is an arithmetic number, because the mean of its divisors is an integer number (3716260369).

Almost surely, 2^28750932721 is an apocalyptic number.

28750932721 is the 169561-st square number.

28750932721 is the 84781-st centered octagonal number.

It is an amenable number.

28750932721 is a deficient number, since it is larger than the sum of its proper divisors (4695410600).

28750932721 is an frugal number, since it uses more digits than its factorization.

28750932721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48460 (or 24230 counting only the distinct ones).

The product of its (nonzero) digits is 423360, while the sum is 46.

The spelling of 28750932721 in words is "twenty-eight billion, seven hundred fifty million, nine hundred thirty-two thousand, seven hundred twenty-one".