1561688855720 has 128 divisors (see below), whose sum is σ = 4043066227200. Its totient is φ = 531809058816.

The previous prime is 1561688855717. The next prime is 1561688855743. The reversal of 1561688855720 is 275588861651.

It is a super-3 number, since 3×1561688855720³ (a number of 38 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24785216 + ... + 24848144.

It is an arithmetic number, because the mean of its divisors is an integer number (31586454900).

Almost surely, 2^{1561688855720} is an apocalyptic number.

1561688855720 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 1561688855720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2021533113600).

1561688855720 is an abundant number, since it is smaller than the sum of its proper divisors (2481377371480).

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

1561688855720 is a wasteful number, since it uses less digits than its factorization.

1561688855720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63547 (or 63543 counting only the distinct ones).

The product of its (nonzero) digits is 32256000, while the sum is 62.

The spelling of 1561688855720 in words is "one trillion, five hundred sixty-one billion, six hundred eighty-eight million, eight hundred fifty-five thousand, seven hundred twenty".