133971918 has 64 divisors (see below), whose sum is σ = 290138112. Its totient is φ = 41136480.

The previous prime is 133971911. The next prime is 133971923. The reversal of 133971918 is 819179331.

It is a self number, because there is not a number n which added to its sum of digits gives 133971918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (133971911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 634833 + ... + 635043.

It is an arithmetic number, because the mean of its divisors is an integer number (4533408).

Almost surely, 2^133971918 is an apocalyptic number.

133971918 is an abundant number, since it is smaller than the sum of its proper divisors (156166194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

133971918 is a wasteful number, since it uses less digits than its factorization.

133971918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389.

The product of its digits is 40824, while the sum is 42.

The square root of 133971918 is about 11574.6238815782. The cubic root of 133971918 is about 511.6872454148.

The spelling of 133971918 in words is "one hundred thirty-three million, nine hundred seventy-one thousand, nine hundred eighteen".