21234556543 has 2 divisors, whose sum is σ = 21234556544. Its totient is φ = 21234556542.

The previous prime is 21234556517. The next prime is 21234556613. The reversal of 21234556543 is 34565543212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21234556543 - 2¹³ = 21234548351 is a prime.

It is a super-2 number, since 2×21234556543² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21234556496 and 21234556505.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21234557543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617278271 + 10617278272.

It is an arithmetic number, because the mean of its divisors is an integer number (10617278272).

Almost surely, 2^21234556543 is an apocalyptic number.

21234556543 is a deficient number, since it is larger than the sum of its proper divisors (1).

21234556543 is an equidigital number, since it uses as much as digits as its factorization.

21234556543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 432000, while the sum is 40.

The spelling of 21234556543 in words is "twenty-one billion, two hundred thirty-four million, five hundred fifty-six thousand, five hundred forty-three".