21235345105 has 32 divisors (see below), whose sum is σ = 28161657216. Its totient is φ = 15272699904.

The previous prime is 21235345037. The next prime is 21235345141. The reversal of 21235345105 is 50154353212.

It is a cyclic number.

It is not a de Polignac number, because 21235345105 - 2¹¹ = 21235343057 is a prime.

It is a super-2 number, since 2×21235345105² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 975874 + ... + 997396.

It is an arithmetic number, because the mean of its divisors is an integer number (880051788).

Almost surely, 2^21235345105 is an apocalyptic number.

It is an amenable number.

21235345105 is a deficient number, since it is larger than the sum of its proper divisors (6926312111).

21235345105 is a wasteful number, since it uses less digits than its factorization.

21235345105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21937.

The product of its (nonzero) digits is 18000, while the sum is 31.

Adding to 21235345105 its reverse (50154353212), we get a palindrome (71389698317).

The spelling of 21235345105 in words is "twenty-one billion, two hundred thirty-five million, three hundred forty-five thousand, one hundred five".