21401324500 has 96 divisors (see below), whose sum is σ = 49326600960. Its totient is φ = 8089200000.

The previous prime is 21401324479. The next prime is 21401324507. The reversal of 21401324500 is 542310412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401324507) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3996825 + ... + 4002175.

It is an arithmetic number, because the mean of its divisors is an integer number (513818760).

Almost surely, 2^21401324500 is an apocalyptic number.

21401324500 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 21401324500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24663300480).

21401324500 is an abundant number, since it is smaller than the sum of its proper divisors (27925276460).

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

21401324500 is a wasteful number, since it uses less digits than its factorization.

21401324500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5810 (or 5798 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21401324500 its reverse (542310412), we get a palindrome (21943634912).

The spelling of 21401324500 in words is "twenty-one billion, four hundred one million, three hundred twenty-four thousand, five hundred".