28207251 has 16 divisors (see below), whose sum is σ = 42499200. Its totient is φ = 18485064.

The previous prime is 28207243. The next prime is 28207261. The reversal of 28207251 is 15270282.

It is not a de Polignac number, because 28207251 - 2³ = 28207243 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (28207261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7261 + ... + 10446.

It is an arithmetic number, because the mean of its divisors is an integer number (2656200).

Almost surely, 2^28207251 is an apocalyptic number.

28207251 is a deficient number, since it is larger than the sum of its proper divisors (14291949).

28207251 is a wasteful number, since it uses less digits than its factorization.

28207251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17775 (or 17769 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 28207251 is about 5311.0498962070. The cubic root of 28207251 is about 304.4062658903.

The spelling of 28207251 in words is "twenty-eight million, two hundred seven thousand, two hundred fifty-one".