18918540 has 72 divisors (see below), whose sum is σ = 58360848. Its totient is φ = 4959360.

The previous prime is 18918539. The next prime is 18918551. The reversal of 18918540 is 4581981.

It is a super-2 number, since 2×18918540² = 715822311463200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18918495 and 18918504.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10119 + ... + 11841.

Almost surely, 2^18918540 is an apocalyptic number.

18918540 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 18918540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29180424).

18918540 is an abundant number, since it is smaller than the sum of its proper divisors (39442308).

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

18918540 is a wasteful number, since it uses less digits than its factorization.

18918540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1799 (or 1794 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The square root of 18918540 is about 4349.5448037697. The cubic root of 18918540 is about 266.4582712127.

It can be divided in two parts, 189185 and 40, that added together give a square (189225 = 435²).

The spelling of 18918540 in words is "eighteen million, nine hundred eighteen thousand, five hundred forty".