28717788 has 24 divisors (see below), whose sum is σ = 73100160. Its totient is φ = 8702320.

The previous prime is 28717781. The next prime is 28717807. The reversal of 28717788 is 88771782.

It is a super-2 number, since 2×28717788² = 1649422695225888, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28717781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 108648 + ... + 108911.

It is an arithmetic number, because the mean of its divisors is an integer number (3045840).

Almost surely, 2^28717788 is an apocalyptic number.

It is an amenable number.

28717788 is an abundant number, since it is smaller than the sum of its proper divisors (44382372).

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

28717788 is a wasteful number, since it uses less digits than its factorization.

28717788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217577 (or 217575 counting only the distinct ones).

The product of its digits is 351232, while the sum is 48.

The square root of 28717788 is about 5358.8980210487. The cubic root of 28717788 is about 306.2318291037.

The spelling of 28717788 in words is "twenty-eight million, seven hundred seventeen thousand, seven hundred eighty-eight".