133421681 has 2 divisors, whose sum is σ = 133421682. Its totient is φ = 133421680.

The previous prime is 133421677. The next prime is 133421683. The reversal of 133421681 is 186124331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 125104225 + 8317456 = 11185^2 + 2884^2 .

It is a cyclic number.

It is not a de Polignac number, because 133421681 - 2² = 133421677 is a prime.

It is a super-2 number, since 2×133421681² = 35602689921731522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 133421683, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (133421683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66710840 + 66710841.

It is an arithmetic number, because the mean of its divisors is an integer number (66710841).

Almost surely, 2^133421681 is an apocalyptic number.

It is an amenable number.

133421681 is a deficient number, since it is larger than the sum of its proper divisors (1).

133421681 is an equidigital number, since it uses as much as digits as its factorization.

133421681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 29.

The square root of 133421681 is about 11550.8303164751. The cubic root of 133421681 is about 510.9857661000.

The spelling of 133421681 in words is "one hundred thirty-three million, four hundred twenty-one thousand, six hundred eighty-one".