18390761 has 4 divisors (see below), whose sum is σ = 18471300. Its totient is φ = 18310224.

The previous prime is 18390733. The next prime is 18390767. The reversal of 18390761 is 16709381.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16483600 + 1907161 = 4060^2 + 1381^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18390761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18390767) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39926 + ... + 40383.

It is an arithmetic number, because the mean of its divisors is an integer number (4617825).

Almost surely, 2^18390761 is an apocalyptic number.

It is an amenable number.

18390761 is a deficient number, since it is larger than the sum of its proper divisors (80539).

18390761 is an equidigital number, since it uses as much as digits as its factorization.

18390761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80538.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 18390761 is about 4288.4450561946. The cubic root of 18390761 is about 263.9570302348.

The spelling of 18390761 in words is "eighteen million, three hundred ninety thousand, seven hundred sixty-one".