18121937 has 4 divisors (see below), whose sum is σ = 18132276. Its totient is φ = 18111600.

The previous prime is 18121921. The next prime is 18121973. The reversal of 18121937 is 73912181.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17048641 + 1073296 = 4129^2 + 1036^2 .

It is a cyclic number.

It is not a de Polignac number, because 18121937 - 2⁴ = 18121921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18121997) 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, 1814 + ... + 6287.

It is an arithmetic number, because the mean of its divisors is an integer number (4533069).

Almost surely, 2^18121937 is an apocalyptic number.

It is an amenable number.

18121937 is a deficient number, since it is larger than the sum of its proper divisors (10339).

18121937 is an equidigital number, since it uses as much as digits as its factorization.

18121937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10338.

The product of its digits is 3024, while the sum is 32.

The square root of 18121937 is about 4256.9868451758. The cubic root of 18121937 is about 262.6645957891.

The spelling of 18121937 in words is "eighteen million, one hundred twenty-one thousand, nine hundred thirty-seven".