28515623 has 4 divisors (see below), whose sum is σ = 29211168. Its totient is φ = 27820080.

The previous prime is 28515611. The next prime is 28515631. The reversal of 28515623 is 32651582.

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 28515623 - 2⁶ = 28515559 is a prime.

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 28515623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28512623) 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, 347711 + ... + 347792.

It is an arithmetic number, because the mean of its divisors is an integer number (7302792).

Almost surely, 2^28515623 is an apocalyptic number.

28515623 is a deficient number, since it is larger than the sum of its proper divisors (695545).

28515623 is an equidigital number, since it uses as much as digits as its factorization.

28515623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695544.

The product of its digits is 14400, while the sum is 32.

The square root of 28515623 is about 5340.0021535576. The cubic root of 28515623 is about 305.5115414631.

The spelling of 28515623 in words is "twenty-eight million, five hundred fifteen thousand, six hundred twenty-three".