21505512732704 has 768 divisors, whose sum is σ = 61337751552000. Its totient is φ = 7151232614400.

The previous prime is 21505512732581. The next prime is 21505512732793. The reversal of 21505512732704 is 40723721550512.

It is a Harshad number since it is a multiple of its sum of digits (44).

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 127 ways as a sum of consecutive naturals, for example, 2793282647 + ... + 2793290345.

It is an arithmetic number, because the mean of its divisors is an integer number (79866864000).

Almost surely, 2^{21505512732704} 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 21505512732704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30668875776000).

21505512732704 is an abundant number, since it is smaller than the sum of its proper divisors (39832238819296).

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

21505512732704 is a wasteful number, since it uses less digits than its factorization.

21505512732704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7897 (or 7889 counting only the distinct ones).

The product of its (nonzero) digits is 588000, while the sum is 44.

The spelling of 21505512732704 in words is "twenty-one trillion, five hundred five billion, five hundred twelve million, seven hundred thirty-two thousand, seven hundred four".