21403432543 has 4 divisors (see below), whose sum is σ = 21404479600. Its totient is φ = 21402385488.

The previous prime is 21403432541. The next prime is 21403432553. The reversal of 21403432543 is 34523430412.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21403432543 - 2¹ = 21403432541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403432541) 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, 492243 + ... + 533956.

It is an arithmetic number, because the mean of its divisors is an integer number (5351119900).

Almost surely, 2^21403432543 is an apocalyptic number.

21403432543 is a deficient number, since it is larger than the sum of its proper divisors (1047057).

21403432543 is a wasteful number, since it uses less digits than its factorization.

21403432543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1047056.

The product of its (nonzero) digits is 34560, while the sum is 31.

Adding to 21403432543 its reverse (34523430412), we get a palindrome (55926862955).

The spelling of 21403432543 in words is "twenty-one billion, four hundred three million, four hundred thirty-two thousand, five hundred forty-three".