87821544409 has 3 divisors (see below), whose sum is σ = 87821840757. Its totient is φ = 87821248062.

The previous prime is 87821544397. The next prime is 87821544413. The reversal of 87821544409 is 90444512878.

The square root of 87821544409 is 296347.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 87821544409 - 2²¹ = 87819447257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87821542409) 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 2 ways as a sum of consecutive naturals, for example, 148174 + ... + 444520.

It is an arithmetic number, because the mean of its divisors is an integer number (29273946919).

Almost surely, 2^87821544409 is an apocalyptic number.

87821544409 is the 296347-th square number.

87821544409 is the 148174-th centered octagonal number.

It is an amenable number.

87821544409 is a deficient number, since it is larger than the sum of its proper divisors (296348).

87821544409 is an frugal number, since it uses more digits than its factorization.

87821544409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592694 (or 296347 counting only the distinct ones).

The product of its (nonzero) digits is 2580480, while the sum is 52.

The spelling of 87821544409 in words is "eighty-seven billion, eight hundred twenty-one million, five hundred forty-four thousand, four hundred nine".