21431113440 has 288 divisors, whose sum is σ = 76603097088. Its totient is φ = 5027404800.

The previous prime is 21431113411. The next prime is 21431113453. The reversal of 21431113440 is 4431113412.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21431113440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1794529 + ... + 1806431.

It is an arithmetic number, because the mean of its divisors is an integer number (265982976).

Almost surely, 2^21431113440 is an apocalyptic number.

21431113440 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 21431113440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38301548544).

21431113440 is an abundant number, since it is smaller than the sum of its proper divisors (55171983648).

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

21431113440 is a wasteful number, since it uses less digits than its factorization.

21431113440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11974 (or 11955 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

Adding to 21431113440 its reverse (4431113412), we get a palindrome (25862226852).

The spelling of 21431113440 in words is "twenty-one billion, four hundred thirty-one million, one hundred thirteen thousand, four hundred forty".