21795543720 has 256 divisors, whose sum is σ = 77043744000. Its totient is φ = 5465346048.

The previous prime is 21795543709. The next prime is 21795543743. The reversal of 21795543720 is 2734559712.

It is a happy number.

21795543720 is a `hidden beast` number, since 2 + 1 + 79 + 554 + 3 + 7 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2807364 + ... + 2815116.

It is an arithmetic number, because the mean of its divisors is an integer number (300952125).

Almost surely, 2^21795543720 is an apocalyptic number.

21795543720 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 21795543720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38521872000).

21795543720 is an abundant number, since it is smaller than the sum of its proper divisors (55248200280).

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

21795543720 is a wasteful number, since it uses less digits than its factorization.

21795543720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7929 (or 7919 counting only the distinct ones).

The product of its (nonzero) digits is 529200, while the sum is 45.

The spelling of 21795543720 in words is "twenty-one billion, seven hundred ninety-five million, five hundred forty-three thousand, seven hundred twenty".