21051343305 has 12 divisors (see below), whose sum is σ = 36488995140. Its totient is φ = 11227383072.

The previous prime is 21051343301. The next prime is 21051343309. The reversal of 21051343305 is 50334315012.

21051343305 is a `hidden beast` number, since 2 + 10 + 5 + 1 + 343 + 305 = 666.

It is an interprime number because it is at equal distance from previous prime (21051343301) and next prime (21051343309).

It can be written as a sum of positive squares in 2 ways, for example, as 15907011129 + 5144332176 = 126123^2 + 71724^2 .

It is not a de Polignac number, because 21051343305 - 2² = 21051343301 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051343301) 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, 233903770 + ... + 233903859.

It is an arithmetic number, because the mean of its divisors is an integer number (3040749595).

Almost surely, 2^21051343305 is an apocalyptic number.

It is an amenable number.

21051343305 is a deficient number, since it is larger than the sum of its proper divisors (15437651835).

21051343305 is a wasteful number, since it uses less digits than its factorization.

21051343305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467807640 (or 467807637 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

Adding to 21051343305 its reverse (50334315012), we get a palindrome (71385658317).

The spelling of 21051343305 in words is "twenty-one billion, fifty-one million, three hundred forty-three thousand, three hundred five".