18403640 has 16 divisors (see below), whose sum is σ = 41408280. Its totient is φ = 7361440.

The previous prime is 18403607. The next prime is 18403643. The reversal of 18403640 is 4630481.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18403643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 230006 + ... + 230085.

Almost surely, 2^18403640 is an apocalyptic number.

18403640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18403640 is an abundant number, since it is smaller than the sum of its proper divisors (23004640).

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

18403640 is a wasteful number, since it uses less digits than its factorization.

18403640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 460102 (or 460098 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 18403640 is about 4289.9463866114. The cubic root of 18403640 is about 264.0186319877.

The spelling of 18403640 in words is "eighteen million, four hundred three thousand, six hundred forty".