21165076220 has 72 divisors (see below), whose sum is σ = 47610302544. Its totient is φ = 7900561152.

The previous prime is 21165076187. The next prime is 21165076241. The reversal of 21165076220 is 2267056112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 461864 + ... + 505616.

It is an arithmetic number, because the mean of its divisors is an integer number (661254202).

Almost surely, 2^21165076220 is an apocalyptic number.

21165076220 is a gapful number since it is divisible by the number (20) 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 21165076220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23805151272).

21165076220 is an abundant number, since it is smaller than the sum of its proper divisors (26445226324).

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

21165076220 is a wasteful number, since it uses less digits than its factorization.

21165076220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43867 (or 43846 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 32.

The spelling of 21165076220 in words is "twenty-one billion, one hundred sixty-five million, seventy-six thousand, two hundred twenty".