16581442220 has 144 divisors (see below), whose sum is σ = 41624458848. Its totient is φ = 5529000960.

The previous prime is 16581442217. The next prime is 16581442237. The reversal of 16581442220 is 2224418561.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22620974 + ... + 22621706.

It is an arithmetic number, because the mean of its divisors is an integer number (289058742).

Almost surely, 2^16581442220 is an apocalyptic number.

16581442220 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 16581442220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20812229424).

16581442220 is an abundant number, since it is smaller than the sum of its proper divisors (25043016628).

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

16581442220 is a wasteful number, since it uses less digits than its factorization.

16581442220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1360 (or 1351 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 35.

The spelling of 16581442220 in words is "sixteen billion, five hundred eighty-one million, four hundred forty-two thousand, two hundred twenty".