1971857 has 2 divisors, whose sum is σ = 1971858. Its totient is φ = 1971856.

The previous prime is 1971833. The next prime is 1971869. The reversal of 1971857 is 7581791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1700416 + 271441 = 1304^2 + 521^2 .

It is a cyclic number.

It is not a de Polignac number, because 1971857 - 2⁸ = 1971601 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1971857.

It is not a weakly prime, because it can be changed into another prime (1971887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 985928 + 985929.

It is an arithmetic number, because the mean of its divisors is an integer number (985929).

2^1971857 is an apocalyptic number.

It is an amenable number.

1971857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1971857 is an equidigital number, since it uses as much as digits as its factorization.

1971857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17640, while the sum is 38.

The square root of 1971857 is about 1404.2282577986. The cubic root of 1971857 is about 125.3983452202.

The spelling of 1971857 in words is "one million, nine hundred seventy-one thousand, eight hundred fifty-seven".