16521204120 has 128 divisors (see below), whose sum is σ = 50508057600. Its totient is φ = 4322502144.

The previous prime is 16521204113. The next prime is 16521204157. The reversal of 16521204120 is 2140212561.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1341109 + ... + 1353371.

It is an arithmetic number, because the mean of its divisors is an integer number (394594200).

Almost surely, 2^16521204120 is an apocalyptic number.

16521204120 is a gapful number since it is divisible by the number (10) 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 16521204120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25254028800).

16521204120 is an abundant number, since it is smaller than the sum of its proper divisors (33986853480).

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

16521204120 is a wasteful number, since it uses less digits than its factorization.

16521204120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12489 (or 12485 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

Adding to 16521204120 its reverse (2140212561), we get a palindrome (18661416681).

The spelling of 16521204120 in words is "sixteen billion, five hundred twenty-one million, two hundred four thousand, one hundred twenty".