21243242020 has 96 divisors (see below), whose sum is σ = 59897085696. Its totient is φ = 6111936000.

The previous prime is 21243241949. The next prime is 21243242039. The reversal of 21243242020 is 2024234212.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 21243241982 and 21243242000.

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, 510531 + ... + 550570.

It is an arithmetic number, because the mean of its divisors is an integer number (623927976).

Almost surely, 2^21243242020 is an apocalyptic number.

21243242020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21243242020 is an abundant number, since it is smaller than the sum of its proper divisors (38653843676).

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

21243242020 is a wasteful number, since it uses less digits than its factorization.

21243242020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061141 (or 1061139 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 22.

Adding to 21243242020 its reverse (2024234212), we get a palindrome (23267476232).

It can be divided in two parts, 212432 and 42020, that added together give a palindrome (254452).

The spelling of 21243242020 in words is "twenty-one billion, two hundred forty-three million, two hundred forty-two thousand, twenty".