194217921 has 12 divisors (see below), whose sum is σ = 288119572. Its totient is φ = 125978976.

The previous prime is 194217899. The next prime is 194217929. The reversal of 194217921 is 129712491.

194217921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 144937521 + 49280400 = 12039^2 + 7020^2 .

It is not a de Polignac number, because 194217921 - 2¹⁸ = 193955777 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (194217929) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 291286 + ... + 291951.

Almost surely, 2^194217921 is an apocalyptic number.

It is an amenable number.

194217921 is a deficient number, since it is larger than the sum of its proper divisors (93901651).

194217921 is a wasteful number, since it uses less digits than its factorization.

194217921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583280 (or 583277 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 194217921 is about 13936.2089895351. The cubic root of 194217921 is about 579.1127148634.

The spelling of 194217921 in words is "one hundred ninety-four million, two hundred seventeen thousand, nine hundred twenty-one".