18506640 has 80 divisors (see below), whose sum is σ = 59371200. Its totient is φ = 4763136.

The previous prime is 18506639. The next prime is 18506671. The reversal of 18506640 is 4660581.

18506640 = T₄₃₁ + T₄₃₂ + ... + T₅₇₅.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 18506598 and 18506607.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5631 + ... + 8289.

It is an arithmetic number, because the mean of its divisors is an integer number (742140).

Almost surely, 2^18506640 is an apocalyptic number.

18506640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18506640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29685600).

18506640 is an abundant number, since it is smaller than the sum of its proper divisors (40864560).

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

18506640 is a wasteful number, since it uses less digits than its factorization.

18506640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2704 (or 2698 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

The square root of 18506640 is about 4301.9344485940. The cubic root of 18506640 is about 264.5102619770.

The spelling of 18506640 in words is "eighteen million, five hundred six thousand, six hundred forty".