21245021105 has 32 divisors (see below), whose sum is σ = 31823947008. Its totient is φ = 13227321600.

The previous prime is 21245021101. The next prime is 21245021111. The reversal of 21245021105 is 50112054212.

It is not a de Polignac number, because 21245021105 - 2² = 21245021101 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21245021101) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 282479 + ... + 349691.

It is an arithmetic number, because the mean of its divisors is an integer number (994498344).

Almost surely, 2^21245021105 is an apocalyptic number.

It is an amenable number.

21245021105 is a deficient number, since it is larger than the sum of its proper divisors (10578925903).

21245021105 is a wasteful number, since it uses less digits than its factorization.

21245021105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68057.

The product of its (nonzero) digits is 800, while the sum is 23.

Adding to 21245021105 its reverse (50112054212), we get a palindrome (71357075317).

The spelling of 21245021105 in words is "twenty-one billion, two hundred forty-five million, twenty-one thousand, one hundred five".