18779897 has 2 divisors, whose sum is σ = 18779898. Its totient is φ = 18779896.

The previous prime is 18779881. The next prime is 18779911. The reversal of 18779897 is 79897781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16168441 + 2611456 = 4021^2 + 1616^2 .

It is an emirp because it is prime and its reverse (79897781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18779897 - 2⁴ = 18779881 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18779807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9389948 + 9389949.

It is an arithmetic number, because the mean of its divisors is an integer number (9389949).

Almost surely, 2^18779897 is an apocalyptic number.

It is an amenable number.

18779897 is a deficient number, since it is larger than the sum of its proper divisors (1).

18779897 is an equidigital number, since it uses as much as digits as its factorization.

18779897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1778112, while the sum is 56.

The square root of 18779897 is about 4333.5778520756. The cubic root of 18779897 is about 265.8057686610.

The spelling of 18779897 in words is "eighteen million, seven hundred seventy-nine thousand, eight hundred ninety-seven".