133181861 has 2 divisors, whose sum is σ = 133181862. Its totient is φ = 133181860.

The previous prime is 133181843. The next prime is 133181869. The reversal of 133181861 is 168181331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82700836 + 50481025 = 9094^2 + 7105^2 .

It is a cyclic number.

It is not a de Polignac number, because 133181861 - 2¹⁰ = 133180837 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133181869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66590930 + 66590931.

It is an arithmetic number, because the mean of its divisors is an integer number (66590931).

Almost surely, 2^133181861 is an apocalyptic number.

It is an amenable number.

133181861 is a deficient number, since it is larger than the sum of its proper divisors (1).

133181861 is an equidigital number, since it uses as much as digits as its factorization.

133181861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 32.

The square root of 133181861 is about 11540.4445754919. Note that the first 3 decimals coincide. The cubic root of 133181861 is about 510.6794238277.

The spelling of 133181861 in words is "one hundred thirty-three million, one hundred eighty-one thousand, eight hundred sixty-one".