812250721665 has 12 divisors (see below), whose sum is σ = 1407901250964. Its totient is φ = 433200384864.

The previous prime is 812250721643. The next prime is 812250721669. The reversal of 812250721665 is 566127052218.

812250721665 is a `hidden beast` number, since 8 + 122 + 507 + 2 + 16 + 6 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 532613878416 + 279636843249 = 729804^2 + 528807^2 .

It is not a de Polignac number, because 812250721665 - 2¹⁰ = 812250720641 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 18050016037 = 812250721665 / (8 + 1 + 2 + 2 + 5 + 0 + 7 + 2 + 1 + 6 + 6 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 812250721665.

It is not an unprimeable number, because it can be changed into a prime (812250721669) 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, 9025007974 + ... + 9025008063.

It is an arithmetic number, because the mean of its divisors is an integer number (117325104247).

Almost surely, 2^812250721665 is an apocalyptic number.

It is an amenable number.

812250721665 is a deficient number, since it is larger than the sum of its proper divisors (595650529299).

812250721665 is a wasteful number, since it uses less digits than its factorization.

812250721665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18050016048 (or 18050016045 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 45.

The spelling of 812250721665 in words is "eight hundred twelve billion, two hundred fifty million, seven hundred twenty-one thousand, six hundred sixty-five".