21940161280 has 72 divisors (see below), whose sum is σ = 52625290032. Its totient is φ = 8764084224.

The previous prime is 21940161211. The next prime is 21940161283. The reversal of 21940161280 is 8216104912.

It is a happy number.

It is a super-2 number, since 2×21940161280² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21940161283) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 957639 + ... + 980281.

It is an arithmetic number, because the mean of its divisors is an integer number (730906806).

Almost surely, 2^21940161280 is an apocalyptic number.

21940161280 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 21940161280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26312645016).

21940161280 is an abundant number, since it is smaller than the sum of its proper divisors (30685128752).

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

21940161280 is an equidigital number, since it uses as much as digits as its factorization.

21940161280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23421 (or 23407 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 21940161280 in words is "twenty-one billion, nine hundred forty million, one hundred sixty-one thousand, two hundred eighty".