28917978 has 16 divisors (see below), whose sum is σ = 59702016. Its totient is φ = 9328320.

The previous prime is 28917953. The next prime is 28918031. The reversal of 28917978 is 87971982.

It is a house number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 28917978.

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, 77551 + ... + 77922.

It is an arithmetic number, because the mean of its divisors is an integer number (3731376).

Almost surely, 2^28917978 is an apocalyptic number.

28917978 is an abundant number, since it is smaller than the sum of its proper divisors (30784038).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28917978 is a wasteful number, since it uses less digits than its factorization.

28917978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155509.

The product of its digits is 508032, while the sum is 51.

The square root of 28917978 is about 5377.5438631405. The cubic root of 28917978 is about 306.9417566797.

The spelling of 28917978 in words is "twenty-eight million, nine hundred seventeen thousand, nine hundred seventy-eight".