28002991 has 8 divisors (see below), whose sum is σ = 28371744. Its totient is φ = 27636960.

The previous prime is 28002971. The next prime is 28003007. The reversal of 28002991 is 19920082.

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

It is a cyclic number.

It is not a de Polignac number, because 28002991 - 2⁹ = 28002479 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28002901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26646 + ... + 27676.

It is an arithmetic number, because the mean of its divisors is an integer number (3546468).

Almost surely, 2^28002991 is an apocalyptic number.

28002991 is a deficient number, since it is larger than the sum of its proper divisors (368753).

28002991 is a wasteful number, since it uses less digits than its factorization.

28002991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 28002991 is about 5291.7852375167. The cubic root of 28002991 is about 303.6697092283.

The spelling of 28002991 in words is "twenty-eight million, two thousand, nine hundred ninety-one".