16521609216 has 240 divisors, whose sum is σ = 52007782400. Its totient is φ = 4565237760.

The previous prime is 16521609187. The next prime is 16521609217. The reversal of 16521609216 is 61290612561.

It is a super-2 number, since 2×16521609216² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16521609217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10665210 + ... + 10666758.

Almost surely, 2^16521609216 is an apocalyptic number.

16521609216 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 16521609216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26003891200).

16521609216 is an abundant number, since it is smaller than the sum of its proper divisors (35486173184).

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

16521609216 is an equidigital number, since it uses as much as digits as its factorization.

16521609216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1618 (or 1592 counting only the distinct ones).

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

The spelling of 16521609216 in words is "sixteen billion, five hundred twenty-one million, six hundred nine thousand, two hundred sixteen".