863161991 has 4 divisors (see below), whose sum is σ = 864033984. Its totient is φ = 862290000.

The previous prime is 863161987. The next prime is 863161993. The reversal of 863161991 is 199161368.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 863161991 - 2² = 863161987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (863161993) 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 3 ways as a sum of consecutive naturals, for example, 434510 + ... + 436491.

It is an arithmetic number, because the mean of its divisors is an integer number (216008496).

Almost surely, 2^863161991 is an apocalyptic number.

863161991 is a deficient number, since it is larger than the sum of its proper divisors (871993).

863161991 is an equidigital number, since it uses as much as digits as its factorization.

863161991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871992.

The product of its digits is 69984, while the sum is 44.

The square root of 863161991 is about 29379.6186326508. The cubic root of 863161991 is about 952.1326018569.

The spelling of 863161991 in words is "eight hundred sixty-three million, one hundred sixty-one thousand, nine hundred ninety-one".