21547352640 has 448 divisors, whose sum is σ = 78372126720. Its totient is φ = 4967424000.

The previous prime is 21547352633. The next prime is 21547352641. The reversal of 21547352640 is 4625374512.

It is not an unprimeable number, because it can be changed into a prime (21547352641) 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, 21742545 + ... + 21743535.

Almost surely, 2^21547352640 is an apocalyptic number.

21547352640 is a gapful number since it is divisible by the number (20) 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 21547352640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39186063360).

21547352640 is an abundant number, since it is smaller than the sum of its proper divisors (56824774080).

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

21547352640 is a wasteful number, since it uses less digits than its factorization.

21547352640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1122 (or 1112 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 39.

The spelling of 21547352640 in words is "twenty-one billion, five hundred forty-seven million, three hundred fifty-two thousand, six hundred forty".