21805465345 has 16 divisors (see below), whose sum is σ = 26774067600. Its totient is φ = 17043206400.

The previous prime is 21805465333. The next prime is 21805465351. The reversal of 21805465345 is 54356450812.

It can be written as a sum of positive squares in 8 ways, for example, as 1741309441 + 20064155904 = 41729^2 + 141648^2 .

It is not a de Polignac number, because 21805465345 - 2¹³ = 21805457153 is a prime.

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, 194466 + ... + 285355.

It is an arithmetic number, because the mean of its divisors is an integer number (1673379225).

Almost surely, 2^21805465345 is an apocalyptic number.

It is an amenable number.

21805465345 is a deficient number, since it is larger than the sum of its proper divisors (4968602255).

21805465345 is a wasteful number, since it uses less digits than its factorization.

21805465345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 480036.

The product of its (nonzero) digits is 576000, while the sum is 43.

The spelling of 21805465345 in words is "twenty-one billion, eight hundred five million, four hundred sixty-five thousand, three hundred forty-five".