194891009 has 4 divisors (see below), whose sum is σ = 206355204. Its totient is φ = 183426816.

The previous prime is 194890979. The next prime is 194891033. The reversal of 194891009 is 900198491.

194891009 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 150601984 + 44289025 = 12272^2 + 6655^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-194891009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (194893009) 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, 5732072 + ... + 5732105.

It is an arithmetic number, because the mean of its divisors is an integer number (51588801).

Almost surely, 2^194891009 is an apocalyptic number.

It is an amenable number.

194891009 is a deficient number, since it is larger than the sum of its proper divisors (11464195).

194891009 is a wasteful number, since it uses less digits than its factorization.

194891009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11464194.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 194891009 is about 13960.3369944998. The cubic root of 194891009 is about 579.7809408574.

The spelling of 194891009 in words is "one hundred ninety-four million, eight hundred ninety-one thousand, nine".