133831661 has 2 divisors, whose sum is σ = 133831662. Its totient is φ = 133831660.

The previous prime is 133831657. The next prime is 133831669. The reversal of 133831661 is 166138331.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 82264900 + 51566761 = 9070^2 + 7181^2 .

It is a cyclic number.

It is not a de Polignac number, because 133831661 - 2² = 133831657 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (133831669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66915830 + 66915831.

It is an arithmetic number, because the mean of its divisors is an integer number (66915831).

Almost surely, 2^133831661 is an apocalyptic number.

It is an amenable number.

133831661 is a deficient number, since it is larger than the sum of its proper divisors (1).

133831661 is an equidigital number, since it uses as much as digits as its factorization.

133831661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 32.

The square root of 133831661 is about 11568.5634803981. The cubic root of 133831661 is about 511.5086189821.

Adding to 133831661 its reverse (166138331), we get a palindrome (299969992).

The spelling of 133831661 in words is "one hundred thirty-three million, eight hundred thirty-one thousand, six hundred sixty-one".