812217641 has 4 divisors (see below), whose sum is σ = 815087952. Its totient is φ = 809347332.

The previous prime is 812217613. The next prime is 812217683. The reversal of 812217641 is 146712218.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-812217641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 812217598 and 812217607.

It is not an unprimeable number, because it can be changed into a prime (812237641) 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, 1434731 + ... + 1435296.

It is an arithmetic number, because the mean of its divisors is an integer number (203771988).

Almost surely, 2^812217641 is an apocalyptic number.

It is an amenable number.

812217641 is a deficient number, since it is larger than the sum of its proper divisors (2870311).

812217641 is a wasteful number, since it uses less digits than its factorization.

812217641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2870310.

The product of its digits is 5376, while the sum is 32.

The square root of 812217641 is about 28499.4322925914. The cubic root of 812217641 is about 933.0196835401.

Adding to 812217641 its reverse (146712218), we get a palindrome (958929859).

The spelling of 812217641 in words is "eight hundred twelve million, two hundred seventeen thousand, six hundred forty-one".