21421122140 has 96 divisors (see below), whose sum is σ = 50767976448. Its totient is φ = 7521696000.

The previous prime is 21421122097. The next prime is 21421122143. The reversal of 21421122140 is 4122112412.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21421122143) 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, 3345422 + ... + 3351818.

It is an arithmetic number, because the mean of its divisors is an integer number (528833088).

Almost surely, 2^21421122140 is an apocalyptic number.

21421122140 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 21421122140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25383988224).

21421122140 is an abundant number, since it is smaller than the sum of its proper divisors (29346854308).

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

21421122140 is a wasteful number, since it uses less digits than its factorization.

21421122140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6939 (or 6937 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21421122140 its reverse (4122112412), we get a palindrome (25543234552).

The spelling of 21421122140 in words is "twenty-one billion, four hundred twenty-one million, one hundred twenty-two thousand, one hundred forty".