18557977 has 2 divisors, whose sum is σ = 18557978. Its totient is φ = 18557976.

The previous prime is 18557971. The next prime is 18557989. The reversal of 18557977 is 77975581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11316496 + 7241481 = 3364^2 + 2691^2 .

It is an emirp because it is prime and its reverse (77975581) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18557977 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18557977.

It is not a weakly prime, because it can be changed into another prime (18557971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9278988 + 9278989.

It is an arithmetic number, because the mean of its divisors is an integer number (9278989).

Almost surely, 2^18557977 is an apocalyptic number.

It is an amenable number.

18557977 is a deficient number, since it is larger than the sum of its proper divisors (1).

18557977 is an equidigital number, since it uses as much as digits as its factorization.

18557977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 617400, while the sum is 49.

The square root of 18557977 is about 4307.8970507662. The cubic root of 18557977 is about 264.7546179944.

The spelling of 18557977 in words is "eighteen million, five hundred fifty-seven thousand, nine hundred seventy-seven".