28709631 has 24 divisors (see below), whose sum is σ = 42456960. Its totient is φ = 18690000.

The previous prime is 28709591. The next prime is 28709633. The reversal of 28709631 is 13690782.

It is not a de Polignac number, because 28709631 - 2¹¹ = 28707583 is a prime.

It is a super-2 number, since 2×28709631² = 1648485824312322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28709633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 114256 + ... + 114506.

It is an arithmetic number, because the mean of its divisors is an integer number (1769040).

Almost surely, 2^28709631 is an apocalyptic number.

28709631 is a deficient number, since it is larger than the sum of its proper divisors (13747329).

28709631 is a wasteful number, since it uses less digits than its factorization.

28709631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507 (or 504 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 28709631 is about 5358.1368963475. The cubic root of 28709631 is about 306.2028323304.

The spelling of 28709631 in words is "twenty-eight million, seven hundred nine thousand, six hundred thirty-one".