21305424305 has 16 divisors (see below), whose sum is σ = 28151406144. Its totient is φ = 15350038080.

The previous prime is 21305424241. The next prime is 21305424313. The reversal of 21305424305 is 50342450312.

It is a happy number.

It is not a de Polignac number, because 21305424305 - 2⁶ = 21305424241 is a prime.

It is a super-2 number, since 2×21305424305² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1804262 + ... + 1816031.

It is an arithmetic number, because the mean of its divisors is an integer number (1759462884).

Almost surely, 2^21305424305 is an apocalyptic number.

It is an amenable number.

21305424305 is a deficient number, since it is larger than the sum of its proper divisors (6845981839).

21305424305 is a wasteful number, since it uses less digits than its factorization.

21305424305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3620416.

The product of its (nonzero) digits is 14400, while the sum is 29.

Adding to 21305424305 its reverse (50342450312), we get a palindrome (71647874617).

The spelling of 21305424305 in words is "twenty-one billion, three hundred five million, four hundred twenty-four thousand, three hundred five".