21879046644 has 192 divisors, whose sum is σ = 65684774400. Its totient is φ = 5628994560.

The previous prime is 21879046643. The next prime is 21879046681. The reversal of 21879046644 is 44664097812.

It is a happy number.

It is a super-3 number, since 3×21879046644³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21879046643) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2188842 + ... + 2198814.

It is an arithmetic number, because the mean of its divisors is an integer number (342108200).

Almost surely, 2^21879046644 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21879046644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32842387200).

21879046644 is an abundant number, since it is smaller than the sum of its proper divisors (43805727756).

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

21879046644 is a wasteful number, since it uses less digits than its factorization.

21879046644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10055 (or 10039 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 51.

The spelling of 21879046644 in words is "twenty-one billion, eight hundred seventy-nine million, forty-six thousand, six hundred forty-four".