28391690 has 16 divisors (see below), whose sum is σ = 51166080. Its totient is φ = 11343120.

The previous prime is 28391687. The next prime is 28391707. The reversal of 28391690 is 9619382.

It is a super-2 number, since 2×28391690² = 1612176122112200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14171 + ... + 16049.

It is an arithmetic number, because the mean of its divisors is an integer number (3197880).

Almost surely, 2^28391690 is an apocalyptic number.

28391690 is a deficient number, since it is larger than the sum of its proper divisors (22774390).

28391690 is a wasteful number, since it uses less digits than its factorization.

28391690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3397.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 28391690 is about 5328.3853088905. The cubic root of 28391690 is about 305.0682996734.

The spelling of 28391690 in words is "twenty-eight million, three hundred ninety-one thousand, six hundred ninety".