18442640 has 40 divisors (see below), whose sum is σ = 43088760. Its totient is φ = 7341056.

The previous prime is 18442639. The next prime is 18442663. The reversal of 18442640 is 4624481.

It can be written as a sum of positive squares in 4 ways, for example, as 1763584 + 16679056 = 1328^2 + 4084^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21092 + ... + 21948.

It is an arithmetic number, because the mean of its divisors is an integer number (1077219).

Almost surely, 2^18442640 is an apocalyptic number.

18442640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18442640 is an abundant number, since it is smaller than the sum of its proper divisors (24646120).

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

18442640 is a wasteful number, since it uses less digits than its factorization.

18442640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1139 (or 1133 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 29.

The square root of 18442640 is about 4294.4894923611. The cubic root of 18442640 is about 264.2049984126.

It can be divided in two parts, 184 and 42640, that added together give a palindrome (42824).

The spelling of 18442640 in words is "eighteen million, four hundred forty-two thousand, six hundred forty".