18390730 has 8 divisors (see below), whose sum is σ = 33103332. Its totient is φ = 7356288.

The previous prime is 18390703. The next prime is 18390733. The reversal of 18390730 is 3709381.

It can be written as a sum of positive squares in 2 ways, for example, as 17230801 + 1159929 = 4151^2 + 1077^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 18390692 and 18390701.

It is not an unprimeable number, because it can be changed into a prime (18390733) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 919527 + ... + 919546.

Almost surely, 2^18390730 is an apocalyptic number.

18390730 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18390730 is a deficient number, since it is larger than the sum of its proper divisors (14712602).

18390730 is a wasteful number, since it uses less digits than its factorization.

18390730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1839080.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 18390730 is about 4288.4414418294. The cubic root of 18390730 is about 263.9568819235.

The spelling of 18390730 in words is "eighteen million, three hundred ninety thousand, seven hundred thirty".