18972540 has 72 divisors (see below), whose sum is σ = 58138080. Its totient is φ = 5007744.

The previous prime is 18972529. The next prime is 18972563. The reversal of 18972540 is 4527981.

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 = 18972495 and 18972504.

It is a congruent number.

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, 19137 + ... + 20103.

Almost surely, 2^18972540 is an apocalyptic number.

18972540 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 18972540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29069040).

18972540 is an abundant number, since it is smaller than the sum of its proper divisors (39165540).

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

18972540 is a wasteful number, since it uses less digits than its factorization.

18972540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1091 (or 1086 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 18972540 is about 4355.7479265908. The cubic root of 18972540 is about 266.7115514724.

The spelling of 18972540 in words is "eighteen million, nine hundred seventy-two thousand, five hundred forty".