18840242 has 4 divisors (see below), whose sum is σ = 28260366. Its totient is φ = 9420120.

The previous prime is 18840223. The next prime is 18840247. The reversal of 18840242 is 24204881.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24204881 = 541 ⋅44741.

It can be written as a sum of positive squares in only one way, i.e., 15531481 + 3308761 = 3941^2 + 1819^2 .

It is not an unprimeable number, because it can be changed into a prime (18840247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4710059 + ... + 4710062.

Almost surely, 2^18840242 is an apocalyptic number.

18840242 is a deficient number, since it is larger than the sum of its proper divisors (9420124).

18840242 is an equidigital number, since it uses as much as digits as its factorization.

18840242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9420123.

The product of its (nonzero) digits is 4096, while the sum is 29.

The square root of 18840242 is about 4340.5347596811. The cubic root of 18840242 is about 266.0901667302.

The spelling of 18840242 in words is "eighteen million, eight hundred forty thousand, two hundred forty-two".