21431657443 has 16 divisors (see below), whose sum is σ = 24682876416. Its totient is φ = 18228188160.

The previous prime is 21431657369. The next prime is 21431657479. The reversal of 21431657443 is 34475613412.

It is not a de Polignac number, because 21431657443 - 2²¹ = 21429560291 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21431657396 and 21431657405.

It is not an unprimeable number, because it can be changed into a prime (21431657483) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 716730 + ... + 746032.

It is an arithmetic number, because the mean of its divisors is an integer number (1542679776).

Almost surely, 2^21431657443 is an apocalyptic number.

21431657443 is a deficient number, since it is larger than the sum of its proper divisors (3251218973).

21431657443 is a wasteful number, since it uses less digits than its factorization.

21431657443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30114.

The product of its digits is 241920, while the sum is 40.

The spelling of 21431657443 in words is "twenty-one billion, four hundred thirty-one million, six hundred fifty-seven thousand, four hundred forty-three".