7891861 has 2 divisors, whose sum is σ = 7891862. Its totient is φ = 7891860.

The previous prime is 7891853. The next prime is 7891867. The reversal of 7891861 is 1681987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7873636 + 18225 = 2806^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 7891861 - 2³ = 7891853 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7891867) by changing a digit.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3945930 + 3945931.

It is an arithmetic number, because the mean of its divisors is an integer number (3945931).

Almost surely, 2^7891861 is an apocalyptic number.

It is an amenable number.

7891861 is a deficient number, since it is larger than the sum of its proper divisors (1).

7891861 is an equidigital number, since it uses as much as digits as its factorization.

7891861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 40.

The square root of 7891861 is about 2809.2456282782. The cubic root of 7891861 is about 199.0947504650.

The spelling of 7891861 in words is "seven million, eight hundred ninety-one thousand, eight hundred sixty-one".