18381977 has 4 divisors (see below), whose sum is σ = 18974976. Its totient is φ = 17788980.

The previous prime is 18381973. The next prime is 18381989. The reversal of 18381977 is 77918381.

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 a cyclic number.

It is not a de Polignac number, because 18381977 - 2² = 18381973 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18381973) 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, 296453 + ... + 296514.

It is an arithmetic number, because the mean of its divisors is an integer number (4743744).

Almost surely, 2^18381977 is an apocalyptic number.

It is an amenable number.

18381977 is a deficient number, since it is larger than the sum of its proper divisors (592999).

18381977 is an equidigital number, since it uses as much as digits as its factorization.

18381977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592998.

The product of its digits is 84672, while the sum is 44.

The square root of 18381977 is about 4287.4207864403. The cubic root of 18381977 is about 263.9149988438.

The spelling of 18381977 in words is "eighteen million, three hundred eighty-one thousand, nine hundred seventy-seven".