1971705091 has 2 divisors, whose sum is σ = 1971705092. Its totient is φ = 1971705090.

The previous prime is 1971705077. The next prime is 1971705097. The reversal of 1971705091 is 1905071791.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1971705091 - 2⁷ = 1971704963 is a prime.

It is not a weakly prime, because it can be changed into another prime (1971705097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985852545 + 985852546.

It is an arithmetic number, because the mean of its divisors is an integer number (985852546).

Almost surely, 2^1971705091 is an apocalyptic number.

1971705091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971705091 is an equidigital number, since it uses as much as digits as its factorization.

1971705091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19845, while the sum is 40.

The square root of 1971705091 is about 44403.8859898545. The cubic root of 1971705091 is about 1253.9512496872.

The spelling of 1971705091 in words is "one billion, nine hundred seventy-one million, seven hundred five thousand, ninety-one".