1581168965840 has 20 divisors (see below), whose sum is σ = 3676217845764. Its totient is φ = 632467586304.

The previous prime is 1581168965837. The next prime is 1581168965863. The reversal of 1581168965840 is 485698611851.

It can be written as a sum of positive squares in 2 ways, for example, as 380496520336 + 1200672445504 = 616844^2 + 1095752^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9882305957 + ... + 9882306116.

Almost surely, 2^{1581168965840} is an apocalyptic number.

1581168965840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1581168965840 is an abundant number, since it is smaller than the sum of its proper divisors (2095048879924).

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

1581168965840 is a wasteful number, since it uses less digits than its factorization.

1581168965840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19764612086 (or 19764612080 counting only the distinct ones).

The product of its (nonzero) digits is 16588800, while the sum is 62.

The spelling of 1581168965840 in words is "one trillion, five hundred eighty-one billion, one hundred sixty-eight million, nine hundred sixty-five thousand, eight hundred forty".