21421243140 has 96 divisors (see below), whose sum is σ = 65931909120. Its totient is φ = 5153366400.

The previous prime is 21421243127. The next prime is 21421243163. The reversal of 21421243140 is 4134212412.

It is a self number, because there is not a number n which added to its sum of digits gives 21421243140.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 37420 + ... + 210339.

It is an arithmetic number, because the mean of its divisors is an integer number (686790720).

Almost surely, 2^21421243140 is an apocalyptic number.

21421243140 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 21421243140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32965954560).

21421243140 is an abundant number, since it is smaller than the sum of its proper divisors (44510665980).

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

21421243140 is a wasteful number, since it uses less digits than its factorization.

21421243140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247913 (or 247911 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21421243140 its reverse (4134212412), we get a palindrome (25555455552).

The spelling of 21421243140 in words is "twenty-one billion, four hundred twenty-one million, two hundred forty-three thousand, one hundred forty".