812861993 has 2 divisors, whose sum is σ = 812861994. Its totient is φ = 812861992.

The previous prime is 812861977. The next prime is 812861999. The reversal of 812861993 is 399168218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 740492944 + 72369049 = 27212^2 + 8507^2 .

It is a cyclic number.

It is not a de Polignac number, because 812861993 - 2⁴ = 812861977 is a prime.

It is not a weakly prime, because it can be changed into another prime (812861999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406430996 + 406430997.

It is an arithmetic number, because the mean of its divisors is an integer number (406430997).

Almost surely, 2^812861993 is an apocalyptic number.

It is an amenable number.

812861993 is a deficient number, since it is larger than the sum of its proper divisors (1).

812861993 is an equidigital number, since it uses as much as digits as its factorization.

812861993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 47.

The square root of 812861993 is about 28510.7346976538. The cubic root of 812861993 is about 933.2663473892.

The spelling of 812861993 in words is "eight hundred twelve million, eight hundred sixty-one thousand, nine hundred ninety-three".