18723040 has 96 divisors (see below), whose sum is σ = 51468480. Its totient is φ = 6303744.

The previous prime is 18723013. The next prime is 18723041. The reversal of 18723040 is 4032781.

18723040 = 470² + 471² + ... + 542².

It is a junction number, because it is equal to n+sod(n) for n = 18722996 and 18723014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18723041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81646 + ... + 81874.

It is an arithmetic number, because the mean of its divisors is an integer number (536130).

Almost surely, 2^18723040 is an apocalyptic number.

18723040 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 18723040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25734240).

18723040 is an abundant number, since it is smaller than the sum of its proper divisors (32745440).

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

18723040 is a wasteful number, since it uses less digits than its factorization.

18723040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324 (or 316 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 18723040 is about 4327.0128264196. The cubic root of 18723040 is about 265.5372511077.

The spelling of 18723040 in words is "eighteen million, seven hundred twenty-three thousand, forty".