18121457 has 4 divisors (see below), whose sum is σ = 18200820. Its totient is φ = 18042096.

The previous prime is 18121429. The next prime is 18121463. The reversal of 18121457 is 75412181.

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 16679056 + 1442401 = 4084^2 + 1201^2 .

It is a cyclic number.

It is not a de Polignac number, because 18121457 - 2⁶ = 18121393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18121417) 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, 39338 + ... + 39795.

It is an arithmetic number, because the mean of its divisors is an integer number (4550205).

Almost surely, 2^18121457 is an apocalyptic number.

It is an amenable number.

18121457 is a deficient number, since it is larger than the sum of its proper divisors (79363).

18121457 is an equidigital number, since it uses as much as digits as its factorization.

18121457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79362.

The product of its digits is 2240, while the sum is 29.

The square root of 18121457 is about 4256.9304668975. The cubic root of 18121457 is about 262.6622766823.

The spelling of 18121457 in words is "eighteen million, one hundred twenty-one thousand, four hundred fifty-seven".