28508531 has 12 divisors (see below), whose sum is σ = 30339792. Its totient is φ = 26782704.

The previous prime is 28508503. The next prime is 28508551. The reversal of 28508531 is 13580582.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-28508531 is a prime.

It is a super-2 number, since 2×28508531² = 1625472679555922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28508551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56426 + ... + 56928.

It is an arithmetic number, because the mean of its divisors is an integer number (2528316).

Almost surely, 2^28508531 is an apocalyptic number.

28508531 is a deficient number, since it is larger than the sum of its proper divisors (1831261).

28508531 is a wasteful number, since it uses less digits than its factorization.

28508531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 698 (or 679 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 28508531 is about 5339.3380675885. The cubic root of 28508531 is about 305.4862118687.

The spelling of 28508531 in words is "twenty-eight million, five hundred eight thousand, five hundred thirty-one".