21405743600 has 60 divisors (see below), whose sum is σ = 51535124160. Its totient is φ = 8544345600.

The previous prime is 21405743563. The next prime is 21405743603. The reversal of 21405743600 is 634750412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405743603) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 135740 + ... + 247460.

It is an arithmetic number, because the mean of its divisors is an integer number (858918736).

Almost surely, 2^21405743600 is an apocalyptic number.

21405743600 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 21405743600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25767562080).

21405743600 is an abundant number, since it is smaller than the sum of its proper divisors (30129380560).

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

21405743600 is a wasteful number, since it uses less digits than its factorization.

21405743600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112218 (or 112207 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 32.

The spelling of 21405743600 in words is "twenty-one billion, four hundred five million, seven hundred forty-three thousand, six hundred".