28991870 has 8 divisors (see below), whose sum is σ = 52185384. Its totient is φ = 11596744.

The previous prime is 28991863. The next prime is 28991873. The reversal of 28991870 is 7819982.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28991873) 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, 1449584 + ... + 1449603.

It is an arithmetic number, because the mean of its divisors is an integer number (6523173).

Almost surely, 2^28991870 is an apocalyptic number.

28991870 is a deficient number, since it is larger than the sum of its proper divisors (23193514).

28991870 is a wasteful number, since it uses less digits than its factorization.

28991870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2899194.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 28991870 is about 5384.4099026727. The cubic root of 28991870 is about 307.2029696142.

The spelling of 28991870 in words is "twenty-eight million, nine hundred ninety-one thousand, eight hundred seventy".