21204112340 has 24 divisors (see below), whose sum is σ = 44548117992. Its totient is φ = 8477934080.

The previous prime is 21204112327. The next prime is 21204112357. The reversal of 21204112340 is 4321140212.

It can be written as a sum of positive squares in 4 ways, for example, as 1560408004 + 19643704336 = 39502^2 + 140156^2 .

It is a super-2 number, since 2×21204112340² (a number of 21 digits) contains 22 as substring.

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

It is a congruent number.

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, 184841 + ... + 276720.

It is an arithmetic number, because the mean of its divisors is an integer number (1856171583).

Almost surely, 2^21204112340 is an apocalyptic number.

21204112340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21204112340 is an abundant number, since it is smaller than the sum of its proper divisors (23344005652).

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

21204112340 is a wasteful number, since it uses less digits than its factorization.

21204112340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 463867 (or 463865 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21204112340 its reverse (4321140212), we get a palindrome (25525252552).

The spelling of 21204112340 in words is "twenty-one billion, two hundred four million, one hundred twelve thousand, three hundred forty".