21443621472 has 432 divisors, whose sum is σ = 76937318640. Its totient is φ = 5615253504.

The previous prime is 21443621461. The next prime is 21443621501. The reversal of 21443621472 is 27412634412.

21443621472 is a `hidden beast` number, since 2 + 1 + 4 + 436 + 214 + 7 + 2 = 666.

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

It is a nude number because it is divisible by every one of its digits.

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 71 ways as a sum of consecutive naturals, for example, 32838298 + ... + 32838950.

It is an arithmetic number, because the mean of its divisors is an integer number (178095645).

Almost surely, 2^21443621472 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 21443621472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38468659320).

21443621472 is an abundant number, since it is smaller than the sum of its proper divisors (55493697168).

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

21443621472 is a wasteful number, since it uses less digits than its factorization.

21443621472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 875 (or 857 counting only the distinct ones).

The product of its digits is 64512, while the sum is 36.

The spelling of 21443621472 in words is "twenty-one billion, four hundred forty-three million, six hundred twenty-one thousand, four hundred seventy-two".