987821893 has 6 divisors (see below), whose sum is σ = 1014716166. Its totient is φ = 960937992.

The previous prime is 987821881. The next prime is 987821909. The reversal of 987821893 is 398128789.

It can be written as a sum of positive squares in only one way, i.e., 961124004 + 26697889 = 31002^2 + 5167^2 .

It is a de Polignac number, because none of the positive numbers 2^k-987821893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (987821833) 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 5 ways as a sum of consecutive naturals, for example, 188596 + ... + 193762.

It is an arithmetic number, because the mean of its divisors is an integer number (169119361).

Almost surely, 2^987821893 is an apocalyptic number.

It is an amenable number.

987821893 is a deficient number, since it is larger than the sum of its proper divisors (26894273).

987821893 is an frugal number, since it uses more digits than its factorization.

987821893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10371 (or 5204 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 55.

The square root of 987821893 is about 31429.6339940509. The cubic root of 987821893 is about 995.9240401230.

The spelling of 987821893 in words is "nine hundred eighty-seven million, eight hundred twenty-one thousand, eight hundred ninety-three".