921774989197 has 4 divisors (see below), whose sum is σ = 921809719836. Its totient is φ = 921740258560.

The previous prime is 921774989183. The next prime is 921774989207. The reversal of 921774989197 is 791989477129.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 791989477129 = 19 ⋅41683656691.

It can be written as a sum of positive squares in 2 ways, for example, as 887601399876 + 34173589321 = 942126^2 + 184861^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921774989197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921774909197) 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, 17325478 + ... + 17378599.

It is an arithmetic number, because the mean of its divisors is an integer number (230452429959).

Almost surely, 2^921774989197 is an apocalyptic number.

It is an amenable number.

921774989197 is a deficient number, since it is larger than the sum of its proper divisors (34730639).

921774989197 is a wasteful number, since it uses less digits than its factorization.

921774989197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34730638.

The product of its digits is 144027072, while the sum is 73.

The spelling of 921774989197 in words is "nine hundred twenty-one billion, seven hundred seventy-four million, nine hundred eighty-nine thousand, one hundred ninety-seven".