1561296816 has 160 divisors (see below), whose sum is σ = 4596134400. Its totient is φ = 507306240.

The previous prime is 1561296797. The next prime is 1561296911. The reversal of 1561296816 is 6186921651.

1561296816 is a `hidden beast` number, since 1 + 561 + 2 + 9 + 6 + 81 + 6 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3343015 + ... + 3343481.

It is an arithmetic number, because the mean of its divisors is an integer number (28725840).

Almost surely, 2^1561296816 is an apocalyptic number.

1561296816 is a gapful number since it is divisible by the number (16) 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 1561296816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2298067200).

1561296816 is an abundant number, since it is smaller than the sum of its proper divisors (3034837584).

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

1561296816 is a wasteful number, since it uses less digits than its factorization.

1561296816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 664 (or 652 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 1561296816 is about 39513.2486135979. The cubic root of 1561296816 is about 1160.0992820296.

The spelling of 1561296816 in words is "one billion, five hundred sixty-one million, two hundred ninety-six thousand, eight hundred sixteen".