21554115543 has 24 divisors (see below), whose sum is σ = 31872881040. Its totient is φ = 14028577920.

The previous prime is 21554115529. The next prime is 21554115547. The reversal of 21554115543 is 34551145512.

21554115543 is a `hidden beast` number, since 2 + 1 + 554 + 11 + 55 + 43 = 666.

It is not a de Polignac number, because 21554115543 - 2¹⁷ = 21553984471 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21554115498 and 21554115507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554115547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 881523 + ... + 905643.

It is an arithmetic number, because the mean of its divisors is an integer number (1328036710).

Almost surely, 2^21554115543 is an apocalyptic number.

21554115543 is a deficient number, since it is larger than the sum of its proper divisors (10318765497).

21554115543 is a wasteful number, since it uses less digits than its factorization.

21554115543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26479 (or 26476 counting only the distinct ones).

The product of its digits is 60000, while the sum is 36.

The spelling of 21554115543 in words is "twenty-one billion, five hundred fifty-four million, one hundred fifteen thousand, five hundred forty-three".