133581993 has 8 divisors (see below), whose sum is σ = 178516800. Its totient is φ = 88850928.

The previous prime is 133581979. The next prime is 133581997. The reversal of 133581993 is 399185331.

It is a happy number.

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

It is not a de Polignac number, because 133581993 - 2⁸ = 133581737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (133581997) 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, 49398 + ... + 52031.

It is an arithmetic number, because the mean of its divisors is an integer number (22314600).

Almost surely, 2^133581993 is an apocalyptic number.

It is an amenable number.

133581993 is a deficient number, since it is larger than the sum of its proper divisors (44934807).

133581993 is a wasteful number, since it uses less digits than its factorization.

133581993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101871.

The product of its digits is 87480, while the sum is 42.

The square root of 133581993 is about 11557.7676477770. The cubic root of 133581993 is about 511.1903414544.

It can be divided in two parts, 13358 and 1993, that added together give a palindrome (15351).

The spelling of 133581993 in words is "one hundred thirty-three million, five hundred eighty-one thousand, nine hundred ninety-three".