28172428 has 24 divisors (see below), whose sum is σ = 51666944. Its totient is φ = 13424400.

The previous prime is 28172407. The next prime is 28172437. The reversal of 28172428 is 82427182.

It is a junction number, because it is equal to n+sod(n) for n = 28172393 and 28172402.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6613 + ... + 10003.

Almost surely, 2^28172428 is an apocalyptic number.

It is an amenable number.

28172428 is a deficient number, since it is larger than the sum of its proper divisors (23494516).

28172428 is a wasteful number, since it uses less digits than its factorization.

28172428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3493 (or 3491 counting only the distinct ones).

The product of its digits is 14336, while the sum is 34.

The square root of 28172428 is about 5307.7705300813. The cubic root of 28172428 is about 304.2809469953.

The spelling of 28172428 in words is "twenty-eight million, one hundred seventy-two thousand, four hundred twenty-eight".