1957861 has 2 divisors, whose sum is σ = 1957862. Its totient is φ = 1957860.

The previous prime is 1957859. The next prime is 1957871. The reversal of 1957861 is 1687591.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1476225 + 481636 = 1215^2 + 694^2 .

It is an emirp because it is prime and its reverse (1687591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1957861 - 2¹ = 1957859 is a prime.

Together with 1957859, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

1957861 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1957861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1957801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 978930 + 978931.

It is an arithmetic number, because the mean of its divisors is an integer number (978931).

2^1957861 is an apocalyptic number.

It is an amenable number.

1957861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1957861 is an equidigital number, since it uses as much as digits as its factorization.

1957861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15120, while the sum is 37.

The square root of 1957861 is about 1399.2358628909. The cubic root of 1957861 is about 125.1009531125.

The spelling of 1957861 in words is "one million, nine hundred fifty-seven thousand, eight hundred sixty-one".