21343253340 has 96 divisors (see below), whose sum is σ = 61254756864. Its totient is φ = 5550969600.

The previous prime is 21343253317. The next prime is 21343253353. The reversal of 21343253340 is 4335234312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21343253298 and 21343253307.

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, 379737 + ... + 432303.

It is an arithmetic number, because the mean of its divisors is an integer number (638070384).

Almost surely, 2^21343253340 is an apocalyptic number.

21343253340 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 21343253340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30627378432).

21343253340 is an abundant number, since it is smaller than the sum of its proper divisors (39911503524).

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

21343253340 is a wasteful number, since it uses less digits than its factorization.

21343253340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52747 (or 52745 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 30.

Adding to 21343253340 its reverse (4335234312), we get a palindrome (25678487652).

The spelling of 21343253340 in words is "twenty-one billion, three hundred forty-three million, two hundred fifty-three thousand, three hundred forty".