21234354345 has 12 divisors (see below), whose sum is σ = 36806214276. Its totient is φ = 11324988960.

The previous prime is 21234354341. The next prime is 21234354347. The reversal of 21234354345 is 54345343212.

21234354345 is a `hidden beast` number, since 212 + 3 + 4 + 3 + 5 + 434 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 10657671696 + 10576682649 = 103236^2 + 102843^2 .

It is not a de Polignac number, because 21234354345 - 2² = 21234354341 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21234354341) 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, 235937226 + ... + 235937315.

It is an arithmetic number, because the mean of its divisors is an integer number (3067184523).

Almost surely, 2^21234354345 is an apocalyptic number.

It is an amenable number.

21234354345 is a deficient number, since it is larger than the sum of its proper divisors (15571859931).

21234354345 is a wasteful number, since it uses less digits than its factorization.

21234354345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 471874552 (or 471874549 counting only the distinct ones).

The product of its digits is 172800, while the sum is 36.

Adding to 21234354345 its reverse (54345343212), we get a palindrome (75579697557).

The spelling of 21234354345 in words is "twenty-one billion, two hundred thirty-four million, three hundred fifty-four thousand, three hundred forty-five".