194680021 has 4 divisors (see below), whose sum is σ = 194794092. Its totient is φ = 194565952.

The previous prime is 194680007. The next prime is 194680037. The reversal of 194680021 is 120086491.

It is a happy number.

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 130279396 + 64400625 = 11414^2 + 8025^2 .

It is a cyclic number.

It is not a de Polignac number, because 194680021 - 2²¹ = 192582869 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (194680001) 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, 54436 + ... + 57901.

It is an arithmetic number, because the mean of its divisors is an integer number (48698523).

Almost surely, 2^194680021 is an apocalyptic number.

It is an amenable number.

194680021 is a deficient number, since it is larger than the sum of its proper divisors (114071).

194680021 is a wasteful number, since it uses less digits than its factorization.

194680021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114070.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 194680021 is about 13952.7782538102. The cubic root of 194680021 is about 579.5716426933.

The spelling of 194680021 in words is "one hundred ninety-four million, six hundred eighty thousand, twenty-one".