812643456 has 64 divisors (see below), whose sum is σ = 2163420000. Its totient is φ = 270274560.

The previous prime is 812643451. The next prime is 812643473. The reversal of 812643456 is 654346218.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (812643451) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189496 + ... + 193736.

Almost surely, 2^812643456 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 812643456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081710000).

812643456 is an abundant number, since it is smaller than the sum of its proper divisors (1350776544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

812643456 is a wasteful number, since it uses less digits than its factorization.

812643456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4757 (or 4745 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 812643456 is about 28506.9019011186. The cubic root of 812643456 is about 933.1827040361.

The spelling of 812643456 in words is "eight hundred twelve million, six hundred forty-three thousand, four hundred fifty-six".