18620120261 has 2 divisors, whose sum is σ = 18620120262. Its totient is φ = 18620120260.

The previous prime is 18620120257. The next prime is 18620120287. The reversal of 18620120261 is 16202102681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10561467361 + 8058652900 = 102769^2 + 89770^2 .

It is a cyclic number.

It is not a de Polignac number, because 18620120261 - 2² = 18620120257 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18620120201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9310060130 + 9310060131.

It is an arithmetic number, because the mean of its divisors is an integer number (9310060131).

Almost surely, 2^18620120261 is an apocalyptic number.

It is an amenable number.

18620120261 is a deficient number, since it is larger than the sum of its proper divisors (1).

18620120261 is an equidigital number, since it uses as much as digits as its factorization.

18620120261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 29.

The spelling of 18620120261 in words is "eighteen billion, six hundred twenty million, one hundred twenty thousand, two hundred sixty-one".