16661420520 has 128 divisors (see below), whose sum is σ = 53040873600. Its totient is φ = 4172496896.

The previous prime is 16661420519. The next prime is 16661420527. The reversal of 16661420520 is 2502416661.

It is not an unprimeable number, because it can be changed into a prime (16661420527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 943936 + ... + 961424.

It is an arithmetic number, because the mean of its divisors is an integer number (414381825).

Almost surely, 2^16661420520 is an apocalyptic number.

16661420520 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 16661420520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26520436800).

16661420520 is an abundant number, since it is smaller than the sum of its proper divisors (36379453080).

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

16661420520 is a wasteful number, since it uses less digits than its factorization.

16661420520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17987 (or 17983 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The spelling of 16661420520 in words is "sixteen billion, six hundred sixty-one million, four hundred twenty thousand, five hundred twenty".