28731993 has 8 divisors (see below), whose sum is σ = 39124608. Its totient is φ = 18747024.

The previous prime is 28731977. The next prime is 28732001. The reversal of 28731993 is 39913782.

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

It is not a de Polignac number, because 28731993 - 2⁴ = 28731977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28731973) 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, 101746 + ... + 102027.

It is an arithmetic number, because the mean of its divisors is an integer number (4890576).

Almost surely, 2^28731993 is an apocalyptic number.

It is an amenable number.

28731993 is a deficient number, since it is larger than the sum of its proper divisors (10392615).

28731993 is a wasteful number, since it uses less digits than its factorization.

28731993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203823.

The product of its digits is 81648, while the sum is 42.

The square root of 28731993 is about 5360.2232229638. The cubic root of 28731993 is about 306.2823124035.

The spelling of 28731993 in words is "twenty-eight million, seven hundred thirty-one thousand, nine hundred ninety-three".