816143991 has 48 divisors (see below), whose sum is σ = 1227327360. Its totient is φ = 479404800.

The previous prime is 816143963. The next prime is 816144019. The reversal of 816143991 is 199341618.

It is an interprime number because it is at equal distance from previous prime (816143963) and next prime (816144019).

It is not a de Polignac number, because 816143991 - 2⁵ = 816143959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816144991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3867876 + ... + 3868086.

It is an arithmetic number, because the mean of its divisors is an integer number (25569320).

Almost surely, 2^816143991 is an apocalyptic number.

816143991 is a deficient number, since it is larger than the sum of its proper divisors (411183369).

816143991 is a wasteful number, since it uses less digits than its factorization.

816143991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 368 (or 327 counting only the distinct ones).

The product of its digits is 46656, while the sum is 42.

The square root of 816143991 is about 28568.2339496161. The cubic root of 816143991 is about 934.5207075761.

The spelling of 816143991 in words is "eight hundred sixteen million, one hundred forty-three thousand, nine hundred ninety-one".