18381377 has 4 divisors (see below), whose sum is σ = 21007296. Its totient is φ = 15755460.

The previous prime is 18381373. The next prime is 18381397. The reversal of 18381377 is 77318381.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 18381377 - 2² = 18381373 is a prime.

It is a super-2 number, since 2×18381377² = 675750040832258, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18381377.

It is not an unprimeable number, because it can be changed into a prime (18381373) 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, 1312949 + ... + 1312962.

It is an arithmetic number, because the mean of its divisors is an integer number (5251824).

Almost surely, 2^18381377 is an apocalyptic number.

It is an amenable number.

18381377 is a deficient number, since it is larger than the sum of its proper divisors (2625919).

18381377 is an equidigital number, since it uses as much as digits as its factorization.

18381377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2625918.

The product of its digits is 28224, while the sum is 38.

The square root of 18381377 is about 4287.3508137310. The cubic root of 18381377 is about 263.9121273587.

The spelling of 18381377 in words is "eighteen million, three hundred eighty-one thousand, three hundred seventy-seven".