812065891 has 8 divisors (see below), whose sum is σ = 999465824. Its totient is φ = 642513600.

The previous prime is 812065883. The next prime is 812065901. The reversal of 812065891 is 198560218.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 812065891 - 2³ = 812065883 is a prime.

It is a super-2 number, since 2×812065891² = 1318902022651247762, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (812065091) 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 in 7 ways as a sum of consecutive naturals, for example, 4461810 + ... + 4461991.

It is an arithmetic number, because the mean of its divisors is an integer number (124933228).

Almost surely, 2^812065891 is an apocalyptic number.

812065891 is a deficient number, since it is larger than the sum of its proper divisors (187399933).

812065891 is a wasteful number, since it uses less digits than its factorization.

812065891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8923821.

The product of its (nonzero) digits is 34560, while the sum is 40.

The square root of 812065891 is about 28496.7698344918. The cubic root of 812065891 is about 932.9615732717.

The spelling of 812065891 in words is "eight hundred twelve million, sixty-five thousand, eight hundred ninety-one".