21131343020 has 24 divisors (see below), whose sum is σ = 44380240800. Its totient is φ = 8451695232.

The previous prime is 21131343001. The next prime is 21131343041. The reversal of 21131343020 is 2034313112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21131342983 and 21131343001.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177776 + ... + 271784.

It is an arithmetic number, because the mean of its divisors is an integer number (1849176700).

Almost surely, 2^21131343020 is an apocalyptic number.

21131343020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21131343020 is an abundant number, since it is smaller than the sum of its proper divisors (23248897780).

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

21131343020 is a wasteful number, since it uses less digits than its factorization.

21131343020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105257 (or 105255 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21131343020 its reverse (2034313112), we get a palindrome (23165656132).

The spelling of 21131343020 in words is "twenty-one billion, one hundred thirty-one million, three hundred forty-three thousand, twenty".