18402442 has 4 divisors (see below), whose sum is σ = 27603666. Its totient is φ = 9201220.

The previous prime is 18402413. The next prime is 18402457. The reversal of 18402442 is 24420481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24420481 = 37 ⋅660013.

It can be written as a sum of positive squares in only one way, i.e., 12257001 + 6145441 = 3501^2 + 2479^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4600609 + ... + 4600612.

Almost surely, 2^18402442 is an apocalyptic number.

18402442 is a deficient number, since it is larger than the sum of its proper divisors (9201224).

18402442 is an equidigital number, since it uses as much as digits as its factorization.

18402442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9201223.

The product of its (nonzero) digits is 2048, while the sum is 25.

The square root of 18402442 is about 4289.8067555544. The cubic root of 18402442 is about 264.0129030271.

The spelling of 18402442 in words is "eighteen million, four hundred two thousand, four hundred forty-two".