817922438661 has 4 divisors (see below), whose sum is σ = 1090563251552. Its totient is φ = 545281625772.

The previous prime is 817922438639. The next prime is 817922438677. The reversal of 817922438661 is 166834229718.

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 not a de Polignac number, because 817922438661 - 2¹⁰ = 817922437637 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (817922439661) 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, 136320406441 + ... + 136320406446.

It is an arithmetic number, because the mean of its divisors is an integer number (272640812888).

Almost surely, 2^817922438661 is an apocalyptic number.

It is an amenable number.

817922438661 is a deficient number, since it is larger than the sum of its proper divisors (272640812891).

817922438661 is a wasteful number, since it uses less digits than its factorization.

817922438661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272640812890.

The product of its digits is 6967296, while the sum is 57.

The spelling of 817922438661 in words is "eight hundred seventeen billion, nine hundred twenty-two million, four hundred thirty-eight thousand, six hundred sixty-one".