28321631 has 12 divisors (see below), whose sum is σ = 31529736. Its totient is φ = 25288560.

The previous prime is 28321627. The next prime is 28321639. The reversal of 28321631 is 13612382.

It is not a de Polignac number, because 28321631 - 2² = 28321627 is a prime.

It is a super-2 number, since 2×28321631² = 1604229565000322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28321631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28321639) 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, 11360 + ... + 13626.

It is an arithmetic number, because the mean of its divisors is an integer number (2627478).

Almost surely, 2^28321631 is an apocalyptic number.

28321631 is a deficient number, since it is larger than the sum of its proper divisors (3208105).

28321631 is a wasteful number, since it uses less digits than its factorization.

28321631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2342 (or 2311 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 28321631 is about 5321.8071178877. The cubic root of 28321631 is about 304.8171653463.

The spelling of 28321631 in words is "twenty-eight million, three hundred twenty-one thousand, six hundred thirty-one".