812172168 has 72 divisors (see below), whose sum is σ = 2219492730. Its totient is φ = 268300800.

The previous prime is 812172149. The next prime is 812172187. The reversal of 812172168 is 861271218.

It is an interprime number because it is at equal distance from previous prime (812172149) and next prime (812172187).

It can be written as a sum of positive squares in 3 ways, for example, as 801003204 + 11168964 = 28302^2 + 3342^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1351068 + ... + 1351668.

Almost surely, 2^812172168 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 812172168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1109746365).

812172168 is an abundant number, since it is smaller than the sum of its proper divisors (1407320562).

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

812172168 is a wasteful number, since it uses less digits than its factorization.

812172168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 887 (or 743 counting only the distinct ones).

The product of its digits is 10752, while the sum is 36.

The square root of 812172168 is about 28498.6344936034. The cubic root of 812172168 is about 933.0022711317.

The spelling of 812172168 in words is "eight hundred twelve million, one hundred seventy-two thousand, one hundred sixty-eight".