21447243732720 has 80 divisors (see below), whose sum is σ = 71600798318112. Its totient is φ = 5279321533440.

The previous prime is 21447243732683. The next prime is 21447243732751. The reversal of 21447243732720 is 2723734274412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21447243732720.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3437055171 + ... + 3437061410.

Almost surely, 2^{21447243732720} is an apocalyptic number.

21447243732720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21447243732720 is an abundant number, since it is smaller than the sum of its proper divisors (50153554585392).

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

21447243732720 is a wasteful number, since it uses less digits than its factorization.

21447243732720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6874116610 (or 6874116604 counting only the distinct ones).

The product of its (nonzero) digits is 3161088, while the sum is 48.

The spelling of 21447243732720 in words is "twenty-one trillion, four hundred forty-seven billion, two hundred forty-three million, seven hundred thirty-two thousand, seven hundred twenty".