21011212305 has 96 divisors (see below), whose sum is σ = 39173116320. Its totient is φ = 10380902400.

The previous prime is 21011212297. The next prime is 21011212331. The reversal of 21011212305 is 50321211012.

It can be written as a sum of positive squares in 16 ways, for example, as 4731238656 + 16279973649 = 68784^2 + 127593^2 .

It is not a de Polignac number, because 21011212305 - 2³ = 21011212297 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 14911441 + ... + 14912849.

It is an arithmetic number, because the mean of its divisors is an integer number (408053295).

Almost surely, 2^21011212305 is an apocalyptic number.

It is an amenable number.

21011212305 is a deficient number, since it is larger than the sum of its proper divisors (18161904015).

21011212305 is a wasteful number, since it uses less digits than its factorization.

21011212305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731 (or 1728 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 21011212305 its reverse (50321211012), we get a palindrome (71332423317).

The spelling of 21011212305 in words is "twenty-one billion, eleven million, two hundred twelve thousand, three hundred five".