15561287280 has 1440 divisors, whose sum is σ = 74095257600. Its totient is φ = 2846638080.

The previous prime is 15561287257. The next prime is 15561287281. The reversal of 15561287280 is 8278216551.

15561287280 is a `hidden beast` number, since 1 + 5 + 5 + 612 + 8 + 7 + 28 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15561287281) by changing a digit.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 196978281 + ... + 196978359.

It is an arithmetic number, because the mean of its divisors is an integer number (51455040).

Almost surely, 2^15561287280 is an apocalyptic number.

15561287280 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 15561287280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37047628800).

15561287280 is an abundant number, since it is smaller than the sum of its proper divisors (58533970320).

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

15561287280 is a wasteful number, since it uses less digits than its factorization.

15561287280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 143 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 45.

The spelling of 15561287280 in words is "fifteen billion, five hundred sixty-one million, two hundred eighty-seven thousand, two hundred eighty".