561611661600 has 144 divisors (see below), whose sum is σ = 1994232048480. Its totient is φ = 136148275200.

The previous prime is 561611661593. The next prime is 561611661697. The reversal of 561611661600 is 6166116165.

It is a super-2 number, since 2×561611661600² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10610185 + ... + 10662984.

It is an arithmetic number, because the mean of its divisors is an integer number (13848833670).

Almost surely, 2^561611661600 is an apocalyptic number.

561611661600 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

561611661600 is an abundant number, since it is smaller than the sum of its proper divisors (1432620386880).

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

561611661600 is a wasteful number, since it uses less digits than its factorization.

561611661600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21273203 (or 21273190 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 39.

Adding to 561611661600 its reverse (6166116165), we get a palindrome (567777777765).

The spelling of 561611661600 in words is "five hundred sixty-one billion, six hundred eleven million, six hundred sixty-one thousand, six hundred".