28640591 has 8 divisors (see below), whose sum is σ = 33530784. Its totient is φ = 23950080.

The previous prime is 28640587. The next prime is 28640609. The reversal of 28640591 is 19504682.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28640591 - 2² = 28640587 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28640551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49610 + ... + 50183.

It is an arithmetic number, because the mean of its divisors is an integer number (4191348).

Almost surely, 2^28640591 is an apocalyptic number.

28640591 is a deficient number, since it is larger than the sum of its proper divisors (4890193).

28640591 is an equidigital number, since it uses as much as digits as its factorization.

28640591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99841.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 28640591 is about 5351.6904805865. The cubic root of 28640591 is about 305.9571864005.

The spelling of 28640591 in words is "twenty-eight million, six hundred forty thousand, five hundred ninety-one".