21522142420 has 48 divisors (see below), whose sum is σ = 46287255168. Its totient is φ = 8401438080.

The previous prime is 21522142393. The next prime is 21522142451. The reversal of 21522142420 is 2424122512.

It is a happy number.

It is a super-2 number, since 2×21522142420² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1053705 + ... + 1073935.

It is an arithmetic number, because the mean of its divisors is an integer number (964317816).

Almost surely, 2^21522142420 is an apocalyptic number.

21522142420 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 21522142420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23143627584).

21522142420 is an abundant number, since it is smaller than the sum of its proper divisors (24765112748).

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

21522142420 is a wasteful number, since it uses less digits than its factorization.

21522142420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21520 (or 21518 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 21522142420 its reverse (2424122512), we get a palindrome (23946264932).

The spelling of 21522142420 in words is "twenty-one billion, five hundred twenty-two million, one hundred forty-two thousand, four hundred twenty".