1581478778880 has 3456 divisors, whose sum is σ = 7830195609600. Its totient is φ = 289839513600.

The previous prime is 1581478778839. The next prime is 1581478778917. The reversal of 1581478778880 is 888778741851.

1581478778880 is a `hidden beast` number, since 1 + 5 + 8 + 1 + 478 + 7 + 78 + 8 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 1581478778799 and 1581478778808.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 20018718681 + ... + 20018718759.

It is an arithmetic number, because the mean of its divisors is an integer number (2265681600).

Almost surely, 2^{1581478778880} is an apocalyptic number.

1581478778880 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 1581478778880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3915097804800).

1581478778880 is an abundant number, since it is smaller than the sum of its proper divisors (6248716830720).

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

1581478778880 is a wasteful number, since it uses less digits than its factorization.

1581478778880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181 (or 151 counting only the distinct ones).

The product of its (nonzero) digits is 224788480, while the sum is 72.

The spelling of 1581478778880 in words is "one trillion, five hundred eighty-one billion, four hundred seventy-eight million, seven hundred seventy-eight thousand, eight hundred eighty".