194138591 has 2 divisors, whose sum is σ = 194138592. Its totient is φ = 194138590.

The previous prime is 194138587. The next prime is 194138611. The reversal of 194138591 is 195831491.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 194138591 - 2² = 194138587 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194138501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97069295 + 97069296.

It is an arithmetic number, because the mean of its divisors is an integer number (97069296).

Almost surely, 2^194138591 is an apocalyptic number.

194138591 is a deficient number, since it is larger than the sum of its proper divisors (1).

194138591 is an equidigital number, since it uses as much as digits as its factorization.

194138591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 41.

The square root of 194138591 is about 13933.3625159184. The cubic root of 194138591 is about 579.0338562496.

The spelling of 194138591 in words is "one hundred ninety-four million, one hundred thirty-eight thousand, five hundred ninety-one".