1865491 has 2 divisors, whose sum is σ = 1865492. Its totient is φ = 1865490.

The previous prime is 1865489. The next prime is 1865509. The reversal of 1865491 is 1945681.

It is a weak prime.

It is an emirp because it is prime and its reverse (1945681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1865491 - 2¹ = 1865489 is a prime.

Together with 1865489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1865411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 932745 + 932746.

It is an arithmetic number, because the mean of its divisors is an integer number (932746).

2^1865491 is an apocalyptic number.

1865491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1865491 is an equidigital number, since it uses as much as digits as its factorization.

1865491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 1865491 is about 1365.8297844168. The cubic root of 1865491 is about 123.1017951236.

The spelling of 1865491 in words is "one million, eight hundred sixty-five thousand, four hundred ninety-one".