21433131420 has 72 divisors (see below), whose sum is σ = 60847029936. Its totient is φ = 5637123072.

The previous prime is 21433131359. The next prime is 21433131427. The reversal of 21433131420 is 2413133412.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21433131427) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 286224 + ... + 353256.

It is an arithmetic number, because the mean of its divisors is an integer number (845097638).

Almost surely, 2^21433131420 is an apocalyptic number.

21433131420 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 21433131420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30423514968).

21433131420 is an abundant number, since it is smaller than the sum of its proper divisors (39413898516).

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

21433131420 is a wasteful number, since it uses less digits than its factorization.

21433131420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67191 (or 67116 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

Adding to 21433131420 its reverse (2413133412), we get a palindrome (23846264832).

The spelling of 21433131420 in words is "twenty-one billion, four hundred thirty-three million, one hundred thirty-one thousand, four hundred twenty".