21601432944 has 320 divisors, whose sum is σ = 78380538880. Its totient is φ = 5542732800.

The previous prime is 21601432903. The next prime is 21601432961. The reversal of 21601432944 is 44923410612.

21601432944 is a `hidden beast` number, since 2 + 1 + 601 + 4 + 3 + 2 + 9 + 44 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21601432899 and 21601432908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1447119 + ... + 1461969.

It is an arithmetic number, because the mean of its divisors is an integer number (244939184).

Almost surely, 2^21601432944 is an apocalyptic number.

21601432944 is a gapful number since it is divisible by the number (24) 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 21601432944, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39190269440).

21601432944 is an abundant number, since it is smaller than the sum of its proper divisors (56779105936).

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

21601432944 is a wasteful number, since it uses less digits than its factorization.

21601432944 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14925 (or 14913 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The spelling of 21601432944 in words is "twenty-one billion, six hundred one million, four hundred thirty-two thousand, nine hundred forty-four".