133645615661 has 2 divisors, whose sum is σ = 133645615662. Its totient is φ = 133645615660.

The previous prime is 133645615657. The next prime is 133645615673. The reversal of 133645615661 is 166516546331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81328202761 + 52317412900 = 285181^2 + 228730^2 .

It is an emirp because it is prime and its reverse (166516546331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 133645615661 - 2² = 133645615657 is a prime.

It is a super-2 number, since 2×133645615661² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133645615861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66822807830 + 66822807831.

It is an arithmetic number, because the mean of its divisors is an integer number (66822807831).

Almost surely, 2^133645615661 is an apocalyptic number.

It is an amenable number.

133645615661 is a deficient number, since it is larger than the sum of its proper divisors (1).

133645615661 is an equidigital number, since it uses as much as digits as its factorization.

133645615661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1166400, while the sum is 47.

The spelling of 133645615661 in words is "one hundred thirty-three billion, six hundred forty-five million, six hundred fifteen thousand, six hundred sixty-one".