15666121894752 has 144 divisors (see below), whose sum is σ = 50966279949312. Its totient is φ = 4471517571840.

The previous prime is 15666121894723. The next prime is 15666121894793. The reversal of 15666121894752 is 25749812166651.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a self number, because there is not a number n which added to its sum of digits gives 15666121894752.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1922878 + ... + 5918589.

It is an arithmetic number, because the mean of its divisors is an integer number (353932499648).

Almost surely, 2^{15666121894752} is an apocalyptic number.

15666121894752 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

15666121894752 is an abundant number, since it is smaller than the sum of its proper divisors (35300158054560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15666121894752 is a wasteful number, since it uses less digits than its factorization.

15666121894752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7842481 (or 7842470 counting only the distinct ones).

The product of its digits is 43545600, while the sum is 63.

The spelling of 15666121894752 in words is "fifteen trillion, six hundred sixty-six billion, one hundred twenty-one million, eight hundred ninety-four thousand, seven hundred fifty-two".