133721257 has 2 divisors, whose sum is σ = 133721258. Its totient is φ = 133721256.

The previous prime is 133721243. The next prime is 133721267. The reversal of 133721257 is 752127331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120912016 + 12809241 = 10996^2 + 3579^2 .

It is a cyclic number.

It is not a de Polignac number, because 133721257 - 2⁷ = 133721129 is a prime.

It is not a weakly prime, because it can be changed into another prime (133721207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66860628 + 66860629.

It is an arithmetic number, because the mean of its divisors is an integer number (66860629).

Almost surely, 2^133721257 is an apocalyptic number.

It is an amenable number.

133721257 is a deficient number, since it is larger than the sum of its proper divisors (1).

133721257 is an equidigital number, since it uses as much as digits as its factorization.

133721257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8820, while the sum is 31.

The square root of 133721257 is about 11563.7907711961. The cubic root of 133721257 is about 511.3679244876.

Adding to 133721257 its reverse (752127331), we get a palindrome (885848588).

The spelling of 133721257 in words is "one hundred thirty-three million, seven hundred twenty-one thousand, two hundred fifty-seven".