133681607981 has 2 divisors, whose sum is σ = 133681607982. Its totient is φ = 133681607980.

The previous prime is 133681607963. The next prime is 133681608001. The reversal of 133681607981 is 189706186331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 124941040900 + 8740567081 = 353470^2 + 93491^2 .

It is an emirp because it is prime and its reverse (189706186331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 133681607981 - 2¹⁴ = 133681591597 is a prime.

It is a super-2 number, since 2×133681607981² (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 (133681607921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66840803990 + 66840803991.

It is an arithmetic number, because the mean of its divisors is an integer number (66840803991).

Almost surely, 2^133681607981 is an apocalyptic number.

It is an amenable number.

133681607981 is a deficient number, since it is larger than the sum of its proper divisors (1).

133681607981 is an equidigital number, since it uses as much as digits as its factorization.

133681607981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1306368, while the sum is 53.

The spelling of 133681607981 in words is "one hundred thirty-three billion, six hundred eighty-one million, six hundred seven thousand, nine hundred eighty-one".