987773288521 has 4 divisors (see below), whose sum is σ = 992012659092. Its totient is φ = 983533917952.

The previous prime is 987773288473. The next prime is 987773288543. The reversal of 987773288521 is 125882377789.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125882377789 = 7 ⋅17983196827.

It can be written as a sum of positive squares in 2 ways, for example, as 341575958025 + 646197330496 = 584445^2 + 803864^2 .

It is a cyclic number.

It is not a de Polignac number, because 987773288521 - 2⁷ = 987773288393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (987773238521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2119684936 + ... + 2119685401.

It is an arithmetic number, because the mean of its divisors is an integer number (248003164773).

Almost surely, 2^987773288521 is an apocalyptic number.

It is an amenable number.

987773288521 is a deficient number, since it is larger than the sum of its proper divisors (4239370571).

987773288521 is a wasteful number, since it uses less digits than its factorization.

987773288521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4239370570.

The product of its digits is 94832640, while the sum is 67.

The spelling of 987773288521 in words is "nine hundred eighty-seven billion, seven hundred seventy-three million, two hundred eighty-eight thousand, five hundred twenty-one".