18161977 has 4 divisors (see below), whose sum is σ = 18380880. Its totient is φ = 17943076.

The previous prime is 18161959. The next prime is 18161981. The reversal of 18161977 is 77916181.

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 18161977 - 2¹⁹ = 17637689 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18161947) 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, 109327 + ... + 109492.

It is an arithmetic number, because the mean of its divisors is an integer number (4595220).

Almost surely, 2^18161977 is an apocalyptic number.

It is an amenable number.

18161977 is a deficient number, since it is larger than the sum of its proper divisors (218903).

18161977 is an equidigital number, since it uses as much as digits as its factorization.

18161977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218902.

The product of its digits is 21168, while the sum is 40.

The square root of 18161977 is about 4261.6871072382. The cubic root of 18161977 is about 262.8579039355.

The spelling of 18161977 in words is "eighteen million, one hundred sixty-one thousand, nine hundred seventy-seven".