28390645 has 4 divisors (see below), whose sum is σ = 34068780. Its totient is φ = 22712512.

The previous prime is 28390633. The next prime is 28390651. The reversal of 28390645 is 54609382.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15816529 + 12574116 = 3977^2 + 3546^2 .

It is a cyclic number.

It is not a de Polignac number, because 28390645 - 2⁵ = 28390613 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2839060 + ... + 2839069.

It is an arithmetic number, because the mean of its divisors is an integer number (8517195).

Almost surely, 2^28390645 is an apocalyptic number.

It is an amenable number.

28390645 is a deficient number, since it is larger than the sum of its proper divisors (5678135).

28390645 is an equidigital number, since it uses as much as digits as its factorization.

28390645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5678134.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 28390645 is about 5328.2872482628. The cubic root of 28390645 is about 305.0645567908.

The spelling of 28390645 in words is "twenty-eight million, three hundred ninety thousand, six hundred forty-five".