18957977 has 4 divisors (see below), whose sum is σ = 18974820. Its totient is φ = 18941136.

The previous prime is 18957973. The next prime is 18957989. The reversal of 18957977 is 77975981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77975981 = 19 ⋅4103999.

It can be written as a sum of positive squares in 2 ways, for example, as 11095561 + 7862416 = 3331^2 + 2804^2 .

It is a cyclic number.

It is not a de Polignac number, because 18957977 - 2² = 18957973 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18957973) 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, 6602 + ... + 9027.

It is an arithmetic number, because the mean of its divisors is an integer number (4743705).

Almost surely, 2^18957977 is an apocalyptic number.

It is an amenable number.

18957977 is a deficient number, since it is larger than the sum of its proper divisors (16843).

18957977 is a wasteful number, since it uses less digits than its factorization.

18957977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16842.

The product of its digits is 1111320, while the sum is 53.

The square root of 18957977 is about 4354.0759065501. The cubic root of 18957977 is about 266.6432929166.

The spelling of 18957977 in words is "eighteen million, nine hundred fifty-seven thousand, nine hundred seventy-seven".