21242443620 has 96 divisors (see below), whose sum is σ = 59991063552. Its totient is φ = 5616044928.

The previous prime is 21242443583. The next prime is 21242443657. The reversal of 21242443620 is 2634424212.

It is an interprime number because it is at equal distance from previous prime (21242443583) and next prime (21242443657).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4330089 + ... + 4334991.

It is an arithmetic number, because the mean of its divisors is an integer number (624906912).

Almost surely, 2^21242443620 is an apocalyptic number.

21242443620 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 21242443620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29995531776).

21242443620 is an abundant number, since it is smaller than the sum of its proper divisors (38748619932).

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

21242443620 is a wasteful number, since it uses less digits than its factorization.

21242443620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5521 (or 5519 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 30.

Adding to 21242443620 its reverse (2634424212), we get a palindrome (23876867832).

The spelling of 21242443620 in words is "twenty-one billion, two hundred forty-two million, four hundred forty-three thousand, six hundred twenty".