21213430433520 has 160 divisors (see below), whose sum is σ = 70831463287872. Its totient is φ = 5220938612736.

The previous prime is 21213430433509. The next prime is 21213430433537. The reversal of 21213430433520 is 2533403431212.

It is a congruent number.

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, 19234974 + ... + 20307906.

Almost surely, 2^{21213430433520} is an apocalyptic number.

21213430433520 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 21213430433520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35415731643936).

21213430433520 is an abundant number, since it is smaller than the sum of its proper divisors (49618032854352).

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

21213430433520 is a wasteful number, since it uses less digits than its factorization.

21213430433520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1079299 (or 1079293 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 33.

Adding to 21213430433520 its reverse (2533403431212), we get a palindrome (23746833864732).

The spelling of 21213430433520 in words is "twenty-one trillion, two hundred thirteen billion, four hundred thirty million, four hundred thirty-three thousand, five hundred twenty".