16561311024 has 80 divisors (see below), whose sum is σ = 43835686400. Its totient is φ = 5384994048.

The previous prime is 16561311001. The next prime is 16561311047. The reversal of 16561311024 is 42011316561.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (16561311001) and next prime (16561311047).

It is a junction number, because it is equal to n+sod(n) for n = 16561310982 and 16561311000.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1706217 + ... + 1715895.

It is an arithmetic number, because the mean of its divisors is an integer number (547946080).

Almost surely, 2^16561311024 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16561311024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21917843200).

16561311024 is an abundant number, since it is smaller than the sum of its proper divisors (27274375376).

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

16561311024 is a wasteful number, since it uses less digits than its factorization.

16561311024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10562 (or 10556 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

Adding to 16561311024 its reverse (42011316561), we get a palindrome (58572627585).

The spelling of 16561311024 in words is "sixteen billion, five hundred sixty-one million, three hundred eleven thousand, twenty-four".