18390073 has 24 divisors (see below), whose sum is σ = 21779928. Its totient is φ = 15455232.

The previous prime is 18390067. The next prime is 18390079. The reversal of 18390073 is 37009381.

It is an interprime number because it is at equal distance from previous prime (18390067) and next prime (18390079).

It can be written as a sum of positive squares in 12 ways, for example, as 514089 + 17875984 = 717^2 + 4228^2 .

It is not a de Polignac number, because 18390073 - 2²¹ = 16292921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18390079) 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 23 ways as a sum of consecutive naturals, for example, 106215 + ... + 106387.

It is an arithmetic number, because the mean of its divisors is an integer number (907497).

Almost surely, 2^18390073 is an apocalyptic number.

18390073 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18390073 is a deficient number, since it is larger than the sum of its proper divisors (3389855).

18390073 is a wasteful number, since it uses less digits than its factorization.

18390073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253 (or 240 counting only the distinct ones).

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

The square root of 18390073 is about 4288.3648398894. The cubic root of 18390073 is about 263.9537386418.

The spelling of 18390073 in words is "eighteen million, three hundred ninety thousand, seventy-three".