194731891 has 2 divisors, whose sum is σ = 194731892. Its totient is φ = 194731890.

The previous prime is 194731871. The next prime is 194731909. The reversal of 194731891 is 198137491.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 194731891 - 2¹³ = 194723699 is a prime.

It is a super-3 number, since 3×194731891³ (a number of 26 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (194731811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97365945 + 97365946.

It is an arithmetic number, because the mean of its divisors is an integer number (97365946).

Almost surely, 2^194731891 is an apocalyptic number.

194731891 is a deficient number, since it is larger than the sum of its proper divisors (1).

194731891 is an equidigital number, since it uses as much as digits as its factorization.

194731891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 43.

The square root of 194731891 is about 13954.6368996115. The cubic root of 194731891 is about 579.6231112713.

The spelling of 194731891 in words is "one hundred ninety-four million, seven hundred thirty-one thousand, eight hundred ninety-one".