28399972 has 12 divisors (see below), whose sum is σ = 49792176. Its totient is φ = 14173640.

The previous prime is 28399949. The next prime is 28399991. The reversal of 28399972 is 27999382.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4054 + ... + 8557.

It is an arithmetic number, because the mean of its divisors is an integer number (4149348).

Almost surely, 2^28399972 is an apocalyptic number.

It is an amenable number.

28399972 is a deficient number, since it is larger than the sum of its proper divisors (21392204).

28399972 is a wasteful number, since it uses less digits than its factorization.

28399972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13178 (or 13176 counting only the distinct ones).

The product of its digits is 489888, while the sum is 49.

The square root of 28399972 is about 5329.1624107359. The cubic root of 28399972 is about 305.0979601131.

The spelling of 28399972 in words is "twenty-eight million, three hundred ninety-nine thousand, nine hundred seventy-two".