21105422421420 has 48 divisors (see below), whose sum is σ = 59546291067648. Its totient is φ = 5585149951680.

The previous prime is 21105422421371. The next prime is 21105422421431. The reversal of 21105422421420 is 2412422450112.

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

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, 1342576264 + ... + 1342591983.

It is an arithmetic number, because the mean of its divisors is an integer number (1240547730576).

Almost surely, 2^{21105422421420} is an apocalyptic number.

21105422421420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21105422421420 is an abundant number, since it is smaller than the sum of its proper divisors (38440868646228).

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

21105422421420 is a wasteful number, since it uses less digits than its factorization.

21105422421420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2685168390 (or 2685168388 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 30.

Adding to 21105422421420 its reverse (2412422450112), we get a palindrome (23517844871532).

The spelling of 21105422421420 in words is "twenty-one trillion, one hundred five billion, four hundred twenty-two million, four hundred twenty-one thousand, four hundred twenty".