18243977 has 4 divisors (see below), whose sum is σ = 18383376. Its totient is φ = 18104580.

The previous prime is 18243959. The next prime is 18243983. The reversal of 18243977 is 77934281.

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 18243977 - 2⁶ = 18243913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18243917) 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, 69503 + ... + 69764.

It is an arithmetic number, because the mean of its divisors is an integer number (4595844).

Almost surely, 2^18243977 is an apocalyptic number.

It is an amenable number.

18243977 is a deficient number, since it is larger than the sum of its proper divisors (139399).

18243977 is a wasteful number, since it uses less digits than its factorization.

18243977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139398.

The product of its digits is 84672, while the sum is 41.

The square root of 18243977 is about 4271.2968756573. The cubic root of 18243977 is about 263.2529048115.

The spelling of 18243977 in words is "eighteen million, two hundred forty-three thousand, nine hundred seventy-seven".