21164705145 has 24 divisors (see below), whose sum is σ = 36695689992. Its totient is φ = 11284704000.

The previous prime is 21164705143. The next prime is 21164705147. The reversal of 21164705145 is 54150746112.

21164705145 is a `hidden beast` number, since 2 + 1 + 1 + 647 + 0 + 5 + 1 + 4 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (21164705143) and next prime (21164705147).

It can be written as a sum of positive squares in 4 ways, for example, as 711128889 + 20453576256 = 26667^2 + 143016^2 .

It is not a de Polignac number, because 21164705145 - 2¹ = 21164705143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21164705143) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 103005 + ... + 230085.

It is an arithmetic number, because the mean of its divisors is an integer number (1528987083).

Almost surely, 2^21164705145 is an apocalyptic number.

It is an amenable number.

21164705145 is a deficient number, since it is larger than the sum of its proper divisors (15530984847).

21164705145 is a wasteful number, since it uses less digits than its factorization.

21164705145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130793 (or 130790 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The spelling of 21164705145 in words is "twenty-one billion, one hundred sixty-four million, seven hundred five thousand, one hundred forty-five".