812391291 has 12 divisors (see below), whose sum is σ = 1242481032. Its totient is φ = 509735616.

The previous prime is 812391271. The next prime is 812391299. The reversal of 812391291 is 192193218.

It is not a de Polignac number, because 812391291 - 2⁵ = 812391259 is a prime.

It is not an unprimeable number, because it can be changed into a prime (812391299) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2654721 + ... + 2655026.

It is an arithmetic number, because the mean of its divisors is an integer number (103540086).

Almost surely, 2^812391291 is an apocalyptic number.

812391291 is a deficient number, since it is larger than the sum of its proper divisors (430089741).

812391291 is a wasteful number, since it uses less digits than its factorization.

812391291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5309770 (or 5309767 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 812391291 is about 28502.4786816866. The cubic root of 812391291 is about 933.0861711886.

The spelling of 812391291 in words is "eight hundred twelve million, three hundred ninety-one thousand, two hundred ninety-one".