133378921 has 4 divisors (see below), whose sum is σ = 143638852. Its totient is φ = 123118992.

The previous prime is 133378907. The next prime is 133378937. The reversal of 133378921 is 129873331.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15960025 + 117418896 = 3995^2 + 10836^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-133378921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133378901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5129946 + ... + 5129971.

It is an arithmetic number, because the mean of its divisors is an integer number (35909713).

Almost surely, 2^133378921 is an apocalyptic number.

It is an amenable number.

133378921 is a deficient number, since it is larger than the sum of its proper divisors (10259931).

133378921 is a wasteful number, since it uses less digits than its factorization.

133378921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10259930.

The product of its digits is 27216, while the sum is 37.

The square root of 133378921 is about 11548.9792189613. The cubic root of 133378921 is about 510.9311720595.

The spelling of 133378921 in words is "one hundred thirty-three million, three hundred seventy-eight thousand, nine hundred twenty-one".