28765631 has 4 divisors (see below), whose sum is σ = 28786392. Its totient is φ = 28744872.

The previous prime is 28765621. The next prime is 28765643. The reversal of 28765631 is 13656782.

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 28765631 - 2⁶ = 28765567 is a prime.

It is a super-2 number, since 2×28765631² = 1654923053656322, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28765621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8141 + ... + 11126.

It is an arithmetic number, because the mean of its divisors is an integer number (7196598).

Almost surely, 2^28765631 is an apocalyptic number.

28765631 is a deficient number, since it is larger than the sum of its proper divisors (20761).

28765631 is a wasteful number, since it uses less digits than its factorization.

28765631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20760.

The product of its digits is 60480, while the sum is 38.

The square root of 28765631 is about 5363.3600475821. The cubic root of 28765631 is about 306.4017925291.

The spelling of 28765631 in words is "twenty-eight million, seven hundred sixty-five thousand, six hundred thirty-one".