812782662521 has 4 divisors (see below), whose sum is σ = 813077900532. Its totient is φ = 812487424512.

The previous prime is 812782662509. The next prime is 812782662541. The reversal of 812782662521 is 125266287218.

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

It can be written as a sum of positive squares in 2 ways, for example, as 438959251600 + 373823410921 = 662540^2 + 611411^2 .

It is a cyclic number.

It is not a de Polignac number, because 812782662521 - 2²² = 812778468217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 812782662521.

It is not an unprimeable number, because it can be changed into a prime (812782662541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147614876 + ... + 147620381.

It is an arithmetic number, because the mean of its divisors is an integer number (203269475133).

Almost surely, 2^812782662521 is an apocalyptic number.

It is an amenable number.

812782662521 is a deficient number, since it is larger than the sum of its proper divisors (295238011).

812782662521 is a wasteful number, since it uses less digits than its factorization.

812782662521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295238010.

The product of its digits is 1290240, while the sum is 50.

The spelling of 812782662521 in words is "eight hundred twelve billion, seven hundred eighty-two million, six hundred sixty-two thousand, five hundred twenty-one".