21344043431 has 4 divisors (see below), whose sum is σ = 21485394864. Its totient is φ = 21202692000.

The previous prime is 21344043389. The next prime is 21344043437. The reversal of 21344043431 is 13434044312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21344043431 is a prime.

It is a super-2 number, since 2×21344043431² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21344043394 and 21344043403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21344043437) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70675490 + ... + 70675791.

It is an arithmetic number, because the mean of its divisors is an integer number (5371348716).

Almost surely, 2^21344043431 is an apocalyptic number.

21344043431 is a deficient number, since it is larger than the sum of its proper divisors (141351433).

21344043431 is a wasteful number, since it uses less digits than its factorization.

21344043431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141351432.

The product of its (nonzero) digits is 13824, while the sum is 29.

Adding to 21344043431 its reverse (13434044312), we get a palindrome (34778087743).

The spelling of 21344043431 in words is "twenty-one billion, three hundred forty-four million, forty-three thousand, four hundred thirty-one".