28731188 has 6 divisors (see below), whose sum is σ = 50279586. Its totient is φ = 14365592.

The previous prime is 28731179. The next prime is 28731191. The reversal of 28731188 is 88113782.

It can be written as a sum of positive squares in only one way, i.e., 23541904 + 5189284 = 4852^2 + 2278^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3591395 + ... + 3591402.

It is an arithmetic number, because the mean of its divisors is an integer number (8379931).

Almost surely, 2^28731188 is an apocalyptic number.

It is an amenable number.

28731188 is a deficient number, since it is larger than the sum of its proper divisors (21548398).

28731188 is a wasteful number, since it uses less digits than its factorization.

28731188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7182801 (or 7182799 counting only the distinct ones).

The product of its digits is 21504, while the sum is 38.

The square root of 28731188 is about 5360.1481322814. The cubic root of 28731188 is about 306.2794519503.

The spelling of 28731188 in words is "twenty-eight million, seven hundred thirty-one thousand, one hundred eighty-eight".