18817801774249 has 2 divisors, whose sum is σ = 18817801774250. Its totient is φ = 18817801774248.

The previous prime is 18817801774241. The next prime is 18817801774273. The reversal of 18817801774249 is 94247710871881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18800618497024 + 17183277225 = 4335968^2 + 131085^2 .

It is a cyclic number.

It is not a de Polignac number, because 18817801774249 - 2³ = 18817801774241 is a prime.

It is a super-2 number, since 2×18817801774249² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18817801774241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9408900887124 + 9408900887125.

It is an arithmetic number, because the mean of its divisors is an integer number (9408900887125).

Almost surely, 2^{18817801774249} is an apocalyptic number.

It is an amenable number.

18817801774249 is a deficient number, since it is larger than the sum of its proper divisors (1).

18817801774249 is an equidigital number, since it uses as much as digits as its factorization.

18817801774249 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 50577408, while the sum is 67.

The spelling of 18817801774249 in words is "eighteen trillion, eight hundred seventeen billion, eight hundred one million, seven hundred seventy-four thousand, two hundred forty-nine".