194921391 has 8 divisors (see below), whose sum is σ = 297023104. Its totient is φ = 111383640.

The previous prime is 194921387. The next prime is 194921411. The reversal of 194921391 is 193129491.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 194921391 - 2² = 194921387 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (194921381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4640965 + ... + 4641006.

It is an arithmetic number, because the mean of its divisors is an integer number (37127888).

Almost surely, 2^194921391 is an apocalyptic number.

194921391 is a deficient number, since it is larger than the sum of its proper divisors (102101713).

194921391 is an equidigital number, since it uses as much as digits as its factorization.

194921391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9281981.

The product of its digits is 17496, while the sum is 39.

The square root of 194921391 is about 13961.4251063421. The cubic root of 194921391 is about 579.8110670792.

The spelling of 194921391 in words is "one hundred ninety-four million, nine hundred twenty-one thousand, three hundred ninety-one".