21521432105 has 16 divisors (see below), whose sum is σ = 25972531200. Its totient is φ = 17119352640.

The previous prime is 21521432083. The next prime is 21521432111. The reversal of 21521432105 is 50123412512.

It is not a de Polignac number, because 21521432105 - 2⁶ = 21521432041 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3204491 + ... + 3211199.

It is an arithmetic number, because the mean of its divisors is an integer number (1623283200).

Almost surely, 2^21521432105 is an apocalyptic number.

It is an amenable number.

21521432105 is a deficient number, since it is larger than the sum of its proper divisors (4451099095).

21521432105 is a wasteful number, since it uses less digits than its factorization.

21521432105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10264.

The product of its (nonzero) digits is 2400, while the sum is 26.

Adding to 21521432105 its reverse (50123412512), we get a palindrome (71644844617).

The spelling of 21521432105 in words is "twenty-one billion, five hundred twenty-one million, four hundred thirty-two thousand, one hundred five".