4171991 has 2 divisors, whose sum is σ = 4171992. Its totient is φ = 4171990.

The previous prime is 4171967. The next prime is 4172029. The reversal of 4171991 is 1991714.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 4171991 - 2¹⁴ = 4155607 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4171931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2085995 + 2085996.

It is an arithmetic number, because the mean of its divisors is an integer number (2085996).

Almost surely, 2^4171991 is an apocalyptic number.

4171991 is a deficient number, since it is larger than the sum of its proper divisors (1).

4171991 is an equidigital number, since it uses as much as digits as its factorization.

4171991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2268, while the sum is 32.

The square root of 4171991 is about 2042.5452259375. The cubic root of 4171991 is about 160.9834094243.

The spelling of 4171991 in words is "four million, one hundred seventy-one thousand, nine hundred ninety-one".