21043434340 has 24 divisors (see below), whose sum is σ = 44258913720. Its totient is φ = 8404478208.

The previous prime is 21043434337. The next prime is 21043434397. The reversal of 21043434340 is 4343434012.

It can be written as a sum of positive squares in 4 ways, for example, as 8573184 + 21034861156 = 2928^2 + 145034^2 .

It is a super-2 number, since 2×21043434340² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21043434299 and 21043434308.

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, 792585 + ... + 818704.

It is an arithmetic number, because the mean of its divisors is an integer number (1844121405).

Almost surely, 2^21043434340 is an apocalyptic number.

21043434340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21043434340 is an abundant number, since it is smaller than the sum of its proper divisors (23215479380).

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

21043434340 is a wasteful number, since it uses less digits than its factorization.

21043434340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611951 (or 1611949 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 28.

Adding to 21043434340 its reverse (4343434012), we get a palindrome (25386868352).

The spelling of 21043434340 in words is "twenty-one billion, forty-three million, four hundred thirty-four thousand, three hundred forty".