981135491 has 4 divisors (see below), whose sum is σ = 1121297712. Its totient is φ = 840973272.

The previous prime is 981135479. The next prime is 981135497. The reversal of 981135491 is 194531189.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-981135491 is a prime.

It is a super-2 number, since 2×981135491² = 1925253703399622162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (981135497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70081100 + ... + 70081113.

It is an arithmetic number, because the mean of its divisors is an integer number (280324428).

Almost surely, 2^981135491 is an apocalyptic number.

981135491 is a deficient number, since it is larger than the sum of its proper divisors (140162221).

981135491 is a wasteful number, since it uses less digits than its factorization.

981135491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140162220.

The product of its digits is 38880, while the sum is 41.

The square root of 981135491 is about 31323.0823994064. The cubic root of 981135491 is about 993.6718695691.

The spelling of 981135491 in words is "nine hundred eighty-one million, one hundred thirty-five thousand, four hundred ninety-one".