561511776 has 144 divisors (see below), whose sum is σ = 1737469440. Its totient is φ = 158296320.

The previous prime is 561511763. The next prime is 561511777. The reversal of 561511776 is 677115165.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561511777) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 370861 + ... + 372371.

It is an arithmetic number, because the mean of its divisors is an integer number (12065760).

Almost surely, 2^561511776 is an apocalyptic number.

561511776 is a gapful number since it is divisible by the number (56) 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 561511776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (868734720).

561511776 is an abundant number, since it is smaller than the sum of its proper divisors (1175957664).

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

561511776 is a wasteful number, since it uses less digits than its factorization.

561511776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617 (or 1602 counting only the distinct ones).

The product of its digits is 44100, while the sum is 39.

The square root of 561511776 is about 23696.2397016911. The cubic root of 561511776 is about 824.9981149636.

It can be divided in two parts, 5615 and 11776, that added together give a triangular number (17391 = T₁₈₆).

The spelling of 561511776 in words is "five hundred sixty-one million, five hundred eleven thousand, seven hundred seventy-six".