133661881 has 2 divisors, whose sum is σ = 133661882. Its totient is φ = 133661880.

The previous prime is 133661867. The next prime is 133661887. The reversal of 133661881 is 188166331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 122877225 + 10784656 = 11085^2 + 3284^2 .

It is a cyclic number.

It is not a de Polignac number, because 133661881 - 2⁹ = 133661369 is a prime.

It is a super-2 number, since 2×133661881² = 35730996864916322, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 133661881.

It is not a weakly prime, because it can be changed into another prime (133661887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66830940 + 66830941.

It is an arithmetic number, because the mean of its divisors is an integer number (66830941).

Almost surely, 2^133661881 is an apocalyptic number.

It is an amenable number.

133661881 is a deficient number, since it is larger than the sum of its proper divisors (1).

133661881 is an equidigital number, since it uses as much as digits as its factorization.

133661881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 37.

The square root of 133661881 is about 11561.2231619323. The cubic root of 133661881 is about 511.2922260343.

The spelling of 133661881 in words is "one hundred thirty-three million, six hundred sixty-one thousand, eight hundred eighty-one".