1856981449 has 2 divisors, whose sum is σ = 1856981450. Its totient is φ = 1856981448.

The previous prime is 1856981431. The next prime is 1856981479. The reversal of 1856981449 is 9441896581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1837665424 + 19316025 = 42868^2 + 4395^2 .

It is a cyclic number.

It is not a de Polignac number, because 1856981449 - 2²³ = 1848592841 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1856981449.

It is not a weakly prime, because it can be changed into another prime (1856981479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 928490724 + 928490725.

It is an arithmetic number, because the mean of its divisors is an integer number (928490725).

Almost surely, 2^1856981449 is an apocalyptic number.

It is an amenable number.

1856981449 is a deficient number, since it is larger than the sum of its proper divisors (1).

1856981449 is an equidigital number, since it uses as much as digits as its factorization.

1856981449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2488320, while the sum is 55.

The square root of 1856981449 is about 43092.7076081325. The cubic root of 1856981449 is about 1229.1433100828.

The spelling of 1856981449 in words is "one billion, eight hundred fifty-six million, nine hundred eighty-one thousand, four hundred forty-nine".