28993087 has 4 divisors (see below), whose sum is σ = 30253680. Its totient is φ = 27732496.

The previous prime is 28993049. The next prime is 28993093. The reversal of 28993087 is 78039982.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28993087 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 (28993787) 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, 630262 + ... + 630307.

It is an arithmetic number, because the mean of its divisors is an integer number (7563420).

Almost surely, 2^28993087 is an apocalyptic number.

28993087 is a deficient number, since it is larger than the sum of its proper divisors (1260593).

28993087 is a wasteful number, since it uses less digits than its factorization.

28993087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1260592.

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 28993087 is about 5384.5229129422. The cubic root of 28993087 is about 307.2072680696.

The spelling of 28993087 in words is "twenty-eight million, nine hundred ninety-three thousand, eighty-seven".