18167381 has 4 divisors (see below), whose sum is σ = 18209772. Its totient is φ = 18124992.

The previous prime is 18167377. The next prime is 18167389. The reversal of 18167381 is 18376181.

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 5564881 + 12602500 = 2359^2 + 3550^2 .

It is a cyclic number.

It is not a de Polignac number, because 18167381 - 2² = 18167377 is a prime.

It is a super-2 number, since 2×18167381² = 660107464798322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18167389) 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, 20546 + ... + 21411.

It is an arithmetic number, because the mean of its divisors is an integer number (4552443).

Almost surely, 2^18167381 is an apocalyptic number.

It is an amenable number.

18167381 is a deficient number, since it is larger than the sum of its proper divisors (42391).

18167381 is an equidigital number, since it uses as much as digits as its factorization.

18167381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42390.

The product of its digits is 8064, while the sum is 35.

The square root of 18167381 is about 4262.3210812889. The cubic root of 18167381 is about 262.8839720089.

The spelling of 18167381 in words is "eighteen million, one hundred sixty-seven thousand, three hundred eighty-one".