1984542891 has 4 divisors (see below), whose sum is σ = 2646057192. Its totient is φ = 1323028592.

The previous prime is 1984542871. The next prime is 1984542929. The reversal of 1984542891 is 1982454891.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1984542891 - 2¹⁴ = 1984526507 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1984542871) 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 in 3 ways as a sum of consecutive naturals, for example, 330757146 + ... + 330757151.

It is an arithmetic number, because the mean of its divisors is an integer number (661514298).

Almost surely, 2^1984542891 is an apocalyptic number.

1984542891 is a deficient number, since it is larger than the sum of its proper divisors (661514301).

1984542891 is an equidigital number, since it uses as much as digits as its factorization.

1984542891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661514300.

The product of its digits is 829440, while the sum is 51.

The square root of 1984542891 is about 44548.2086171824. The cubic root of 1984542891 is about 1256.6668625528. Note that the first 3 decimals are identical.

The spelling of 1984542891 in words is "one billion, nine hundred eighty-four million, five hundred forty-two thousand, eight hundred ninety-one".