18640720 has 40 divisors (see below), whose sum is σ = 49532544. Its totient is φ = 6390912.

The previous prime is 18640693. The next prime is 18640723. The reversal of 18640720 is 2704681.

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

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18640723) 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, 16084 + ... + 17203.

Almost surely, 2^18640720 is an apocalyptic number.

18640720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18640720 is an abundant number, since it is smaller than the sum of its proper divisors (30891824).

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

18640720 is a wasteful number, since it uses less digits than its factorization.

18640720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33307 (or 33301 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 18640720 is about 4317.4900115692. The cubic root of 18640720 is about 265.1475148788.

The spelling of 18640720 in words is "eighteen million, six hundred forty thousand, seven hundred twenty".