1975991 has 2 divisors, whose sum is σ = 1975992. Its totient is φ = 1975990.

The previous prime is 1975957. The next prime is 1975997. The reversal of 1975991 is 1995791.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1975991 - 2¹⁰ = 1974967 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1975997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 987995 + 987996.

It is an arithmetic number, because the mean of its divisors is an integer number (987996).

2^1975991 is an apocalyptic number.

1975991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1975991 is an equidigital number, since it uses as much as digits as its factorization.

1975991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25515, while the sum is 41.

The square root of 1975991 is about 1405.6994700148. The cubic root of 1975991 is about 125.4859166326.

The spelling of 1975991 in words is "one million, nine hundred seventy-five thousand, nine hundred ninety-one".