21105503541 has 12 divisors (see below), whose sum is σ = 31002435360. Its totient is φ = 13831855080.

The previous prime is 21105503537. The next prime is 21105503603. The reversal of 21105503541 is 14530550112.

21105503541 is a `hidden beast` number, since 2 + 1 + 105 + 503 + 54 + 1 = 666.

It is not a de Polignac number, because 21105503541 - 2² = 21105503537 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105503641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19872825 + ... + 19873886.

It is an arithmetic number, because the mean of its divisors is an integer number (2583536280).

Almost surely, 2^21105503541 is an apocalyptic number.

It is an amenable number.

21105503541 is a deficient number, since it is larger than the sum of its proper divisors (9896931819).

21105503541 is a wasteful number, since it uses less digits than its factorization.

21105503541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39746776 (or 39746773 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 21105503541 in words is "twenty-one billion, one hundred five million, five hundred three thousand, five hundred forty-one".