772228521 has 27 divisors (see below), whose sum is σ = 1141940631. Its totient is φ = 502869744.

The previous prime is 772228493. The next prime is 772228531. The reversal of 772228521 is 125822277.

The square root of 772228521 is 27789.

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., 226352025 + 545876496 = 15045^2 + 23364^2 .

It is not a de Polignac number, because 772228521 - 2⁵ = 772228489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (772228531) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 4918575 + ... + 4918731.

Almost surely, 2^772228521 is an apocalyptic number.

772228521 is the 27789-th square number.

772228521 is the 13895-th centered octagonal number.

It is an amenable number.

772228521 is a deficient number, since it is larger than the sum of its proper divisors (369712110).

772228521 is an equidigital number, since it uses as much as digits as its factorization.

772228521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438 (or 219 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The cubic root of 772228521 is about 917.4490300269.

Multiplying 772228521 by its sum of digits (36), we get a square (27800226756 = 166734²).

The spelling of 772228521 in words is "seven hundred seventy-two million, two hundred twenty-eight thousand, five hundred twenty-one".