16561399296 has 160 divisors (see below), whose sum is σ = 48414088800. Its totient is φ = 4999348224.

The previous prime is 16561399277. The next prime is 16561399307. The reversal of 16561399296 is 69299316561.

It is a happy number.

It is a congruent number.

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, 1050480 + ... + 1066128.

It is an arithmetic number, because the mean of its divisors is an integer number (302588055).

Almost surely, 2^16561399296 is an apocalyptic number.

16561399296 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 16561399296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24207044400).

16561399296 is an abundant number, since it is smaller than the sum of its proper divisors (31852689504).

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

16561399296 is a wasteful number, since it uses less digits than its factorization.

16561399296 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15736 (or 15720 counting only the distinct ones).

The product of its digits is 4723920, while the sum is 57.

The spelling of 16561399296 in words is "sixteen billion, five hundred sixty-one million, three hundred ninety-nine thousand, two hundred ninety-six".