1861042889 has 2 divisors, whose sum is σ = 1861042890. Its totient is φ = 1861042888.

The previous prime is 1861042811. The next prime is 1861042891. The reversal of 1861042889 is 9882401681.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1336999225 + 524043664 = 36565^2 + 22892^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861042889 - 2²⁸ = 1592607433 is a prime.

Together with 1861042891, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1861047889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 930521444 + 930521445.

It is an arithmetic number, because the mean of its divisors is an integer number (930521445).

Almost surely, 2^1861042889 is an apocalyptic number.

It is an amenable number.

1861042889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1861042889 is an equidigital number, since it uses as much as digits as its factorization.

1861042889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 221184, while the sum is 47.

The square root of 1861042889 is about 43139.8063162087. The cubic root of 1861042889 is about 1230.0387519463.

The spelling of 1861042889 in words is "one billion, eight hundred sixty-one million, forty-two thousand, eight hundred eighty-nine".