18236440 has 32 divisors (see below), whose sum is σ = 41298480. Its totient is φ = 7247232.

The previous prime is 18236437. The next prime is 18236443. The reversal of 18236440 is 4463281.

It is an interprime number because it is at equal distance from previous prime (18236437) and next prime (18236443).

It is a junction number, because it is equal to n+sod(n) for n = 18236399 and 18236408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18236443) 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, 5122 + ... + 7918.

Almost surely, 2^18236440 is an apocalyptic number.

18236440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18236440 is an abundant number, since it is smaller than the sum of its proper divisors (23062040).

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

18236440 is a wasteful number, since it uses less digits than its factorization.

18236440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2971 (or 2967 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 18236440 is about 4270.4144997880. The cubic root of 18236440 is about 263.2166479062.

The spelling of 18236440 in words is "eighteen million, two hundred thirty-six thousand, four hundred forty".