181998541494431 has 4 divisors (see below), whose sum is σ = 182111373821832. Its totient is φ = 181885709167032.

The previous prime is 181998541494421. The next prime is 181998541494479. The reversal of 181998541494431 is 134494145899181.

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-181998541494431 is a prime.

It is a super-2 number, since 2×181998541494431² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181998541494421) 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, 56416161281 + ... + 56416164506.

It is an arithmetic number, because the mean of its divisors is an integer number (45527843455458).

Almost surely, 2^{181998541494431} is an apocalyptic number.

181998541494431 is a deficient number, since it is larger than the sum of its proper divisors (112832327401).

181998541494431 is a wasteful number, since it uses less digits than its factorization.

181998541494431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112832327400.

The product of its digits is 179159040, while the sum is 71.

The spelling of 181998541494431 in words is "one hundred eighty-one trillion, nine hundred ninety-eight billion, five hundred forty-one million, four hundred ninety-four thousand, four hundred thirty-one".