16665221055420 has 480 divisors, whose sum is σ = 60453195264000. Its totient is φ = 3764276499456.

The previous prime is 16665221055409. The next prime is 16665221055451. The reversal of 16665221055420 is 2455012256661.

It is a super-2 number, since 2×16665221055420² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 2421211299 + ... + 2421218181.

It is an arithmetic number, because the mean of its divisors is an integer number (125944156800).

Almost surely, 2^{16665221055420} is an apocalyptic number.

16665221055420 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 16665221055420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30226597632000).

16665221055420 is an abundant number, since it is smaller than the sum of its proper divisors (43787974208580).

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

16665221055420 is a wasteful number, since it uses less digits than its factorization.

16665221055420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9399 (or 9388 counting only the distinct ones).

The product of its (nonzero) digits is 864000, while the sum is 45.

The spelling of 16665221055420 in words is "sixteen trillion, six hundred sixty-five billion, two hundred twenty-one million, fifty-five thousand, four hundred twenty".