13661665601 has 2 divisors, whose sum is σ = 13661665602. Its totient is φ = 13661665600.

The previous prime is 13661665583. The next prime is 13661665643. The reversal of 13661665601 is 10656616631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12684165376 + 977500225 = 112624^2 + 31265^2 .

It is a cyclic number.

It is not a de Polignac number, because 13661665601 - 2¹⁴ = 13661649217 is a prime.

It is a super-2 number, since 2×13661665601² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13661665201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6830832800 + 6830832801.

It is an arithmetic number, because the mean of its divisors is an integer number (6830832801).

Almost surely, 2^13661665601 is an apocalyptic number.

It is an amenable number.

13661665601 is a deficient number, since it is larger than the sum of its proper divisors (1).

13661665601 is an equidigital number, since it uses as much as digits as its factorization.

13661665601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 116640, while the sum is 41.

The spelling of 13661665601 in words is "thirteen billion, six hundred sixty-one million, six hundred sixty-five thousand, six hundred one".