28328631 has 4 divisors (see below), whose sum is σ = 37771512. Its totient is φ = 18885752.

The previous prime is 28328627. The next prime is 28328633. The reversal of 28328631 is 13682382.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28328631 - 2² = 28328627 is a prime.

It is a super-2 number, since 2×28328631² = 1605022668668322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28328592 and 28328601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28328633) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4721436 + ... + 4721441.

It is an arithmetic number, because the mean of its divisors is an integer number (9442878).

Almost surely, 2^28328631 is an apocalyptic number.

28328631 is a deficient number, since it is larger than the sum of its proper divisors (9442881).

28328631 is an equidigital number, since it uses as much as digits as its factorization.

28328631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9442880.

The product of its digits is 13824, while the sum is 33.

The square root of 28328631 is about 5322.4647485916. The cubic root of 28328631 is about 304.8422762400.

The spelling of 28328631 in words is "twenty-eight million, three hundred twenty-eight thousand, six hundred thirty-one".