15987778560 has 396 divisors, whose sum is σ = 60015575412. Its totient is φ = 3933536256.

The previous prime is 15987778559. The next prime is 15987778633. The reversal of 15987778560 is 6587778951.

It can be written as a sum of positive squares in 6 ways, for example, as 3068273664 + 12919504896 = 55392^2 + 113664^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7786494 + ... + 7788546.

Almost surely, 2^15987778560 is an apocalyptic number.

15987778560 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15987778560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30007787706).

15987778560 is an abundant number, since it is smaller than the sum of its proper divisors (44027796852).

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

15987778560 is a wasteful number, since it uses less digits than its factorization.

15987778560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2110 (or 2076 counting only the distinct ones).

The product of its (nonzero) digits is 29635200, while the sum is 63.

The spelling of 15987778560 in words is "fifteen billion, nine hundred eighty-seven million, seven hundred seventy-eight thousand, five hundred sixty".