812172169 has 4 divisors (see below), whose sum is σ = 815542420. Its totient is φ = 808801920.

The previous prime is 812172149. The next prime is 812172187. The reversal of 812172169 is 961271218.

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 545829769 + 266342400 = 23363^2 + 16320^2 .

It is a cyclic number.

It is not a de Polignac number, because 812172169 - 2⁷ = 812172041 is a prime.

It is a super-2 number, since 2×812172169² = 1319247264196329122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (812172139) 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, 1684764 + ... + 1685245.

It is an arithmetic number, because the mean of its divisors is an integer number (203885605).

Almost surely, 2^812172169 is an apocalyptic number.

It is an amenable number.

812172169 is a deficient number, since it is larger than the sum of its proper divisors (3370251).

812172169 is a wasteful number, since it uses less digits than its factorization.

812172169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3370250.

The product of its digits is 12096, while the sum is 37.

The square root of 812172169 is about 28498.6345111481. The cubic root of 812172169 is about 933.0022715147.

The spelling of 812172169 in words is "eight hundred twelve million, one hundred seventy-two thousand, one hundred sixty-nine".