981191231 has 4 divisors (see below), whose sum is σ = 983753472. Its totient is φ = 978628992.

The previous prime is 981191221. The next prime is 981191291. The reversal of 981191231 is 132191189.

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-981191231 is a prime.

It is a super-2 number, since 2×981191231² = 1925472463582590722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 981191191 and 981191200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (981191221) 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, 1280546 + ... + 1281311.

It is an arithmetic number, because the mean of its divisors is an integer number (245938368).

Almost surely, 2^981191231 is an apocalyptic number.

981191231 is a deficient number, since it is larger than the sum of its proper divisors (2562241).

981191231 is a wasteful number, since it uses less digits than its factorization.

981191231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2562240.

The product of its digits is 3888, while the sum is 35.

The square root of 981191231 is about 31323.9721459460. The cubic root of 981191231 is about 993.6906866172.

The spelling of 981191231 in words is "nine hundred eighty-one million, one hundred ninety-one thousand, two hundred thirty-one".