21043542405 has 32 divisors (see below), whose sum is σ = 34560609408. Its totient is φ = 10929888000.

The previous prime is 21043542389. The next prime is 21043542413. The reversal of 21043542405 is 50424534012.

It is not a de Polignac number, because 21043542405 - 2⁴ = 21043542389 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21439 + ... + 206268.

It is an arithmetic number, because the mean of its divisors is an integer number (1080019044).

Almost surely, 2^21043542405 is an apocalyptic number.

It is an amenable number.

21043542405 is a deficient number, since it is larger than the sum of its proper divisors (13517067003).

21043542405 is a wasteful number, since it uses less digits than its factorization.

21043542405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227877.

The product of its (nonzero) digits is 19200, while the sum is 30.

The spelling of 21043542405 in words is "twenty-one billion, forty-three million, five hundred forty-two thousand, four hundred five".