1987083921 has 4 divisors (see below), whose sum is σ = 2649445232. Its totient is φ = 1324722612.

The previous prime is 1987083863. The next prime is 1987083929. The reversal of 1987083921 is 1293807891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1987083921 - 2¹⁰ = 1987082897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987083929) 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, 331180651 + ... + 331180656.

It is an arithmetic number, because the mean of its divisors is an integer number (662361308).

Almost surely, 2^1987083921 is an apocalyptic number.

It is an amenable number.

1987083921 is a deficient number, since it is larger than the sum of its proper divisors (662361311).

1987083921 is an equidigital number, since it uses as much as digits as its factorization.

1987083921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 662361310.

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 1987083921 is about 44576.7194957188. The cubic root of 1987083921 is about 1257.2029837086.

The spelling of 1987083921 in words is "one billion, nine hundred eighty-seven million, eighty-three thousand, nine hundred twenty-one".