133444561 has 2 divisors, whose sum is σ = 133444562. Its totient is φ = 133444560.

The previous prime is 133444559. The next prime is 133444567. The reversal of 133444561 is 165444331.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133263936 + 180625 = 11544^2 + 425^2 .

It is a cyclic number.

It is not a de Polignac number, because 133444561 - 2¹ = 133444559 is a prime.

Together with 133444559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (133444567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66722280 + 66722281.

It is an arithmetic number, because the mean of its divisors is an integer number (66722281).

Almost surely, 2^133444561 is an apocalyptic number.

It is an amenable number.

133444561 is a deficient number, since it is larger than the sum of its proper divisors (1).

133444561 is an equidigital number, since it uses as much as digits as its factorization.

133444561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 31.

The square root of 133444561 is about 11551.8206790099. The cubic root of 133444561 is about 511.0149734622.

Adding to 133444561 its reverse (165444331), we get a palindrome (298888892).

The spelling of 133444561 in words is "one hundred thirty-three million, four hundred forty-four thousand, five hundred sixty-one".