18977 has 4 divisors (see below), whose sum is σ = 21696. Its totient is φ = 16260.

The previous prime is 18973. The next prime is 18979. The reversal of 18977 is 77981.

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, and also an emirpimes, since its reverse is a distinct semiprime: 77981 = 29 ⋅2689.

It is a cyclic number.

It is not a de Polignac number, because 18977 - 2² = 18973 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1349 + ... + 1362.

It is an arithmetic number, because the mean of its divisors is an integer number (5424).

2¹⁸⁹⁷⁷ is an apocalyptic number.

It is an amenable number.

18977 is a deficient number, since it is larger than the sum of its proper divisors (2719).

18977 is an equidigital number, since it uses as much as digits as its factorization.

18977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2718.

The product of its digits is 3528, while the sum is 32.

The square root of 18977 is about 137.7570324884. The cubic root of 18977 is about 26.6732449049.

The spelling of 18977 in words is "eighteen thousand, nine hundred seventy-seven".