28772225 has 18 divisors (see below), whose sum is σ = 36522774. Its totient is φ = 22484800.

The previous prime is 28772197. The next prime is 28772257. The reversal of 28772225 is 52227782.

28772225 = 582² + 583² + ... + 656².

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 565504 + 28206721 = 752^2 + 5311^2 .

It is not a de Polignac number, because 28772225 - 2¹⁰ = 28771201 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 54965 + ... + 55485.

It is an arithmetic number, because the mean of its divisors is an integer number (2029043).

Almost surely, 2^28772225 is an apocalyptic number.

28772225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28772225 is a deficient number, since it is larger than the sum of its proper divisors (7750549).

28772225 is an equidigital number, since it uses as much as digits as its factorization.

28772225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625 (or 573 counting only the distinct ones).

The product of its digits is 31360, while the sum is 35.

The square root of 28772225 is about 5363.9747389413. The cubic root of 28772225 is about 306.4252030945.

The spelling of 28772225 in words is "twenty-eight million, seven hundred seventy-two thousand, two hundred twenty-five".