28491390 has 24 divisors (see below), whose sum is σ = 74077848. Its totient is φ = 7597680.

The previous prime is 28491367. The next prime is 28491409. The reversal of 28491390 is 9319482.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 158196 + ... + 158375.

It is an arithmetic number, because the mean of its divisors is an integer number (3086577).

Almost surely, 2^28491390 is an apocalyptic number.

28491390 is an abundant number, since it is smaller than the sum of its proper divisors (45586458).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28491390 is a wasteful number, since it uses less digits than its factorization.

28491390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316584 (or 316581 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 28491390 is about 5337.7326647182. The cubic root of 28491390 is about 305.4249741878.

The spelling of 28491390 in words is "twenty-eight million, four hundred ninety-one thousand, three hundred ninety".