133688381 has 2 divisors, whose sum is σ = 133688382. Its totient is φ = 133688380.

The previous prime is 133688377. The next prime is 133688431. The reversal of 133688381 is 183886331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118156900 + 15531481 = 10870^2 + 3941^2 .

It is a cyclic number.

It is not a de Polignac number, because 133688381 - 2² = 133688377 is a prime.

It is a super-2 number, since 2×133688381² = 35745166428802322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133688311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66844190 + 66844191.

It is an arithmetic number, because the mean of its divisors is an integer number (66844191).

Almost surely, 2^133688381 is an apocalyptic number.

It is an amenable number.

133688381 is a deficient number, since it is larger than the sum of its proper divisors (1).

133688381 is an equidigital number, since it uses as much as digits as its factorization.

133688381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 41.

The square root of 133688381 is about 11562.3691776383. The cubic root of 133688381 is about 511.3260136496.

The spelling of 133688381 in words is "one hundred thirty-three million, six hundred eighty-eight thousand, three hundred eighty-one".