21549664752 has 320 divisors, whose sum is σ = 72509644800. Its totient is φ = 5350947840.

The previous prime is 21549664603. The next prime is 21549664753. The reversal of 21549664752 is 25746694512.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21549664695 and 21549664704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21549664753) 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, 11467749 + ... + 11469627.

It is an arithmetic number, because the mean of its divisors is an integer number (226592640).

Almost surely, 2^21549664752 is an apocalyptic number.

21549664752 is a gapful number since it is divisible by the number (22) 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 21549664752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36254822400).

21549664752 is an abundant number, since it is smaller than the sum of its proper divisors (50959980048).

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

21549664752 is a wasteful number, since it uses less digits than its factorization.

21549664752 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2044 (or 2038 counting only the distinct ones).

The product of its digits is 3628800, while the sum is 51.

The spelling of 21549664752 in words is "twenty-one billion, five hundred forty-nine million, six hundred sixty-four thousand, seven hundred fifty-two".