31800133 has 4 divisors (see below), whose sum is σ = 32575788. Its totient is φ = 31024480.

The previous prime is 31800127. The next prime is 31800137. The reversal of 31800133 is 33100813.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4739329 + 27060804 = 2177^2 + 5202^2 .

It is a cyclic number.

It is not a de Polignac number, because 31800133 - 2⁵ = 31800101 is a prime.

It is a super-2 number, since 2×31800133² = 2022496917635378, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31800133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31800137) 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, 387766 + ... + 387847.

It is an arithmetic number, because the mean of its divisors is an integer number (8143947).

Almost surely, 2^31800133 is an apocalyptic number.

It is an amenable number.

31800133 is a deficient number, since it is larger than the sum of its proper divisors (775655).

31800133 is an equidigital number, since it uses as much as digits as its factorization.

31800133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 775654.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 31800133 is about 5639.1606644961. The cubic root of 31800133 is about 316.8178522158.

Adding to 31800133 its reverse (33100813), we get a palindrome (64900946).

The spelling of 31800133 in words is "thirty-one million, eight hundred thousand, one hundred thirty-three".