13920665861 has 2 divisors, whose sum is σ = 13920665862. Its totient is φ = 13920665860.

The previous prime is 13920665839. The next prime is 13920665893. The reversal of 13920665861 is 16856602931.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13733496100 + 187169761 = 117190^2 + 13681^2 .

It is a cyclic number.

It is not a de Polignac number, because 13920665861 - 2²² = 13916471557 is a prime.

It is a super-2 number, since 2×13920665861² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13920665461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6960332930 + 6960332931.

It is an arithmetic number, because the mean of its divisors is an integer number (6960332931).

Almost surely, 2^13920665861 is an apocalyptic number.

It is an amenable number.

13920665861 is a deficient number, since it is larger than the sum of its proper divisors (1).

13920665861 is an equidigital number, since it uses as much as digits as its factorization.

13920665861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 47.

The spelling of 13920665861 in words is "thirteen billion, nine hundred twenty million, six hundred sixty-five thousand, eight hundred sixty-one".