18775997 has 2 divisors, whose sum is σ = 18775998. Its totient is φ = 18775996.

The previous prime is 18775969. The next prime is 18776029. The reversal of 18775997 is 79957781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18438436 + 337561 = 4294^2 + 581^2 .

It is an emirp because it is prime and its reverse (79957781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18775997 - 2²⁰ = 17727421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18775957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9387998 + 9387999.

It is an arithmetic number, because the mean of its divisors is an integer number (9387999).

Almost surely, 2^18775997 is an apocalyptic number.

It is an amenable number.

18775997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18775997 is an equidigital number, since it uses as much as digits as its factorization.

18775997 is an evil number, because the sum of its binary digits is even.

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

The square root of 18775997 is about 4333.1278541026. The cubic root of 18775997 is about 265.7873675259.

The spelling of 18775997 in words is "eighteen million, seven hundred seventy-five thousand, nine hundred ninety-seven".