133721281 has 6 divisors (see below), whose sum is σ = 134373570. Its totient is φ = 133072128.

The previous prime is 133721267. The next prime is 133721299. The reversal of 133721281 is 182127331.

It can be written as a sum of positive squares in only one way, i.e., 79566400 + 54154881 = 8920^2 + 7359^2 .

It is not a de Polignac number, because 133721281 - 2¹¹ = 133719233 is a prime.

It is a super-2 number, since 2×133721281² = 35762761984561922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133721381) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 48385 + ... + 51073.

It is an arithmetic number, because the mean of its divisors is an integer number (22395595).

Almost surely, 2^133721281 is an apocalyptic number.

It is an amenable number.

133721281 is a deficient number, since it is larger than the sum of its proper divisors (652289).

133721281 is an frugal number, since it uses more digits than its factorization.

133721281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3135 (or 2912 counting only the distinct ones).

The product of its digits is 2016, while the sum is 28.

The square root of 133721281 is about 11563.7918089180. The cubic root of 133721281 is about 511.3679550807.

The spelling of 133721281 in words is "one hundred thirty-three million, seven hundred twenty-one thousand, two hundred eighty-one".