21051247543 has 24 divisors (see below), whose sum is σ = 23593686800. Its totient is φ = 18726847488.

The previous prime is 21051247537. The next prime is 21051247549. The reversal of 21051247543 is 34574215012.

It is an interprime number because it is at equal distance from previous prime (21051247537) and next prime (21051247549).

It is not a de Polignac number, because 21051247543 - 2³³ = 12461312951 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21051247499 and 21051247508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051247549) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2505193 + ... + 2513581.

Almost surely, 2^21051247543 is an apocalyptic number.

21051247543 is a deficient number, since it is larger than the sum of its proper divisors (2542439257).

21051247543 is a wasteful number, since it uses less digits than its factorization.

21051247543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8899 (or 8882 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 34.

The spelling of 21051247543 in words is "twenty-one billion, fifty-one million, two hundred forty-seven thousand, five hundred forty-three".