28731994 has 4 divisors (see below), whose sum is σ = 43097994. Its totient is φ = 14365996.

The previous prime is 28731977. The next prime is 28732001. The reversal of 28731994 is 49913782.

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

It can be written as a sum of positive squares in only one way, i.e., 24631369 + 4100625 = 4963^2 + 2025^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 28731994.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7182997 + ... + 7183000.

Almost surely, 2^28731994 is an apocalyptic number.

28731994 is a deficient number, since it is larger than the sum of its proper divisors (14366000).

28731994 is a wasteful number, since it uses less digits than its factorization.

28731994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14365999.

The product of its digits is 108864, while the sum is 43.

The square root of 28731994 is about 5360.2233162435. The cubic root of 28731994 is about 306.2823159568.

The spelling of 28731994 in words is "twenty-eight million, seven hundred thirty-one thousand, nine hundred ninety-four".