18440238 has 16 divisors (see below), whose sum is σ = 37386576. Its totient is φ = 6062400.

The previous prime is 18440231. The next prime is 18440251. The reversal of 18440238 is 83204481.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18440231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20613 + ... + 21488.

It is an arithmetic number, because the mean of its divisors is an integer number (2336661).

Almost surely, 2^18440238 is an apocalyptic number.

18440238 is an abundant number, since it is smaller than the sum of its proper divisors (18946338).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18440238 is a wasteful number, since it uses less digits than its factorization.

18440238 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42179.

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 18440238 is about 4294.2098225401. The cubic root of 18440238 is about 264.1935277490.

The spelling of 18440238 in words is "eighteen million, four hundred forty thousand, two hundred thirty-eight".