18121738 has 4 divisors (see below), whose sum is σ = 27182610. Its totient is φ = 9060868.

The previous prime is 18121721. The next prime is 18121759. The reversal of 18121738 is 83712181.

It is a happy number.

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., 12909649 + 5212089 = 3593^2 + 2283^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4530433 + ... + 4530436.

Almost surely, 2^18121738 is an apocalyptic number.

18121738 is a deficient number, since it is larger than the sum of its proper divisors (9060872).

18121738 is an equidigital number, since it uses as much as digits as its factorization.

18121738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9060871.

The product of its digits is 2688, while the sum is 31.

The square root of 18121738 is about 4256.9634717719. The cubic root of 18121738 is about 262.6636343310.

It can be divided in two parts, 1812173 and 8, that added together give a palindrome (1812181).

The spelling of 18121738 in words is "eighteen million, one hundred twenty-one thousand, seven hundred thirty-eight".