16587999978561 has 12 divisors (see below), whose sum is σ = 26138666633040. Its totient is φ = 10053333320280.

The previous prime is 16587999978521. The next prime is 16587999978601.

16587999978561 is a `hidden beast` number, since 16 + 587 + 9 + 9 + 9 + 9 + 7 + 8 + 5 + 6 + 1 = 666.

16587999978561 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (16587999978521) and next prime (16587999978601).

It is not a de Polignac number, because 16587999978561 - 2²² = 16587995784257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16587999978521) 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 11 ways as a sum of consecutive naturals, for example, 83777777571 + ... + 83777777768.

It is an arithmetic number, because the mean of its divisors is an integer number (2178222219420).

Almost surely, 2^{16587999978561} is an apocalyptic number.

16587999978561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16587999978561 is a deficient number, since it is larger than the sum of its proper divisors (9550666654479).

16587999978561 is a wasteful number, since it uses less digits than its factorization.

16587999978561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167555555356 (or 167555555353 counting only the distinct ones).

The product of its digits is 18517766400, while the sum is 90.

The spelling of 16587999978561 in words is "sixteen trillion, five hundred eighty-seven billion, nine hundred ninety-nine million, nine hundred seventy-eight thousand, five hundred sixty-one".