28312731 has 12 divisors (see below), whose sum is σ = 41414880. Its totient is φ = 18635760.

The previous prime is 28312727. The next prime is 28312751. The reversal of 28312731 is 13721382.

It is not a de Polignac number, because 28312731 - 2² = 28312727 is a prime.

It is a super-2 number, since 2×28312731² = 1603221473356722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28312695 and 28312704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28312721) 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, 19200 + ... + 20621.

It is an arithmetic number, because the mean of its divisors is an integer number (3451240).

Almost surely, 2^28312731 is an apocalyptic number.

28312731 is a deficient number, since it is larger than the sum of its proper divisors (13102149).

28312731 is a wasteful number, since it uses less digits than its factorization.

28312731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39906 (or 39903 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 28312731 is about 5320.9708700575. The cubic root of 28312731 is about 304.7852326633.

The spelling of 28312731 in words is "twenty-eight million, three hundred twelve thousand, seven hundred thirty-one".