133321721 has 8 divisors (see below), whose sum is σ = 143876544. Its totient is φ = 122809680.

The previous prime is 133321697. The next prime is 133321723. The reversal of 133321721 is 127123331.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 133321721 - 2¹⁰ = 133320697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133321723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4061 + ... + 16826.

It is an arithmetic number, because the mean of its divisors is an integer number (17984568).

Almost surely, 2^133321721 is an apocalyptic number.

It is an amenable number.

133321721 is a deficient number, since it is larger than the sum of its proper divisors (10554823).

133321721 is a wasteful number, since it uses less digits than its factorization.

133321721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21391.

The product of its digits is 756, while the sum is 23.

The square root of 133321721 is about 11546.5025440607. The cubic root of 133321721 is about 510.8581234308.

The spelling of 133321721 in words is "one hundred thirty-three million, three hundred twenty-one thousand, seven hundred twenty-one".