133409681 has 2 divisors, whose sum is σ = 133409682. Its totient is φ = 133409680.

The previous prime is 133409671. The next prime is 133409687. The reversal of 133409681 is 186904331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119159056 + 14250625 = 10916^2 + 3775^2 .

It is an emirp because it is prime and its reverse (186904331) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 133409681 - 2¹⁰ = 133408657 is a prime.

It is a super-3 number, since 3×133409681³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is equal to p_7560485 and since 133409681 and 7560485 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (133409687) 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, 66704840 + 66704841.

It is an arithmetic number, because the mean of its divisors is an integer number (66704841).

Almost surely, 2^133409681 is an apocalyptic number.

It is an amenable number.

133409681 is a deficient number, since it is larger than the sum of its proper divisors (1).

133409681 is an equidigital number, since it uses as much as digits as its factorization.

133409681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 133409681 is about 11550.3108616175. The cubic root of 133409681 is about 510.9704462185.

The spelling of 133409681 in words is "one hundred thirty-three million, four hundred nine thousand, six hundred eighty-one".