21423144340 has 48 divisors (see below), whose sum is σ = 48929020560. Its totient is φ = 7831756800.

The previous prime is 21423144331. The next prime is 21423144373. The reversal of 21423144340 is 4344132412.

It can be written as a sum of positive squares in 8 ways, for example, as 3207863044 + 18215281296 = 56638^2 + 134964^2 .

It is a super-2 number, since 2×21423144340² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21423144299 and 21423144308.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 381645 + ... + 434164.

It is an arithmetic number, because the mean of its divisors is an integer number (1019354595).

Almost surely, 2^21423144340 is an apocalyptic number.

21423144340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21423144340 is an abundant number, since it is smaller than the sum of its proper divisors (27505876220).

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

21423144340 is a wasteful number, since it uses less digits than its factorization.

21423144340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815932 (or 815930 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

Adding to 21423144340 its reverse (4344132412), we get a palindrome (25767276752).

The spelling of 21423144340 in words is "twenty-one billion, four hundred twenty-three million, one hundred forty-four thousand, three hundred forty".