28997631 has 48 divisors (see below), whose sum is σ = 48746880. Its totient is φ = 16450560.

The previous prime is 28997623. The next prime is 28997653. The reversal of 28997631 is 13679982.

28997631 is a `hidden beast` number, since 2 + 8 + 9 + 9 + 7 + 631 = 666.

It is not a de Polignac number, because 28997631 - 2³ = 28997623 is a prime.

It is a super-2 number, since 2×28997631² = 1681725207224322, which contains 22 as substring.

Its product of digits (163296) is a multiple of the sum of its prime factors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28997231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 121210 + ... + 121448.

It is an arithmetic number, because the mean of its divisors is an integer number (1015560).

Almost surely, 2^28997631 is an apocalyptic number.

28997631 is a deficient number, since it is larger than the sum of its proper divisors (19749249).

28997631 is a wasteful number, since it uses less digits than its factorization.

28997631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 336 (or 333 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 28997631 is about 5384.9448465142. The cubic root of 28997631 is about 307.2233164574.

The spelling of 28997631 in words is "twenty-eight million, nine hundred ninety-seven thousand, six hundred thirty-one".