133891491 has 16 divisors (see below), whose sum is σ = 181644800. Its totient is φ = 87710688.

The previous prime is 133891489. The next prime is 133891501. The reversal of 133891491 is 194198331.

It is a happy number.

It is not a de Polignac number, because 133891491 - 2¹ = 133891489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (133891411) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53040 + ... + 55506.

It is an arithmetic number, because the mean of its divisors is an integer number (11352800).

Almost surely, 2^133891491 is an apocalyptic number.

133891491 is a deficient number, since it is larger than the sum of its proper divisors (47753309).

133891491 is a wasteful number, since it uses less digits than its factorization.

133891491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2778.

The product of its digits is 23328, while the sum is 39.

The square root of 133891491 is about 11571.1490786352. The cubic root of 133891491 is about 511.5848316438.

It can be divided in two parts, 1338 and 91491, that added together give a palindrome (92829).

The spelling of 133891491 in words is "one hundred thirty-three million, eight hundred ninety-one thousand, four hundred ninety-one".