28256631 has 12 divisors (see below), whose sum is σ = 40797288. Its totient is φ = 17388384.

The previous prime is 28256623. The next prime is 28256653. The reversal of 28256631 is 13665282.

It is not a de Polignac number, because 28256631 - 2³ = 28256623 is a prime.

It is a super-2 number, since 2×28256631² = 1596874390940322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28256592 and 28256601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28256131) 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, 27360 + ... + 28373.

It is an arithmetic number, because the mean of its divisors is an integer number (3399774).

Almost surely, 2^28256631 is an apocalyptic number.

28256631 is a deficient number, since it is larger than the sum of its proper divisors (12540657).

28256631 is a wasteful number, since it uses less digits than its factorization.

28256631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55762 (or 55749 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 28256631 is about 5315.6966617744. The cubic root of 28256631 is about 304.5837949286.

The spelling of 28256631 in words is "twenty-eight million, two hundred fifty-six thousand, six hundred thirty-one".