28331818 has 4 divisors (see below), whose sum is σ = 42497730. Its totient is φ = 14165908.

The previous prime is 28331803. The next prime is 28331819. The reversal of 28331818 is 81813382.

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., 17918289 + 10413529 = 4233^2 + 3227^2 .

It is a super-2 number, since 2×28331818² = 1605383822370248, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28331819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7082953 + ... + 7082956.

Almost surely, 2^28331818 is an apocalyptic number.

28331818 is a deficient number, since it is larger than the sum of its proper divisors (14165912).

28331818 is a wasteful number, since it uses less digits than its factorization.

28331818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14165911.

The product of its digits is 9216, while the sum is 34.

The square root of 28331818 is about 5322.7641315392. The cubic root of 28331818 is about 304.8537075007.

The spelling of 28331818 in words is "twenty-eight million, three hundred thirty-one thousand, eight hundred eighteen".