664254895821 has 16 divisors (see below), whose sum is σ = 970198033728. Its totient is φ = 400908268800.

The previous prime is 664254895819. The next prime is 664254895823. The reversal of 664254895821 is 128598452466.

It is an interprime number because it is at equal distance from previous prime (664254895819) and next prime (664254895823).

It is not a de Polignac number, because 664254895821 - 2¹ = 664254895819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664254895823) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41753326 + ... + 41769231.

It is an arithmetic number, because the mean of its divisors is an integer number (60637377108).

Almost surely, 2^664254895821 is an apocalyptic number.

It is an amenable number.

664254895821 is a deficient number, since it is larger than the sum of its proper divisors (305943137907).

664254895821 is a wasteful number, since it uses less digits than its factorization.

664254895821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83522812.

The product of its digits is 33177600, while the sum is 60.

The spelling of 664254895821 in words is "six hundred sixty-four billion, two hundred fifty-four million, eight hundred ninety-five thousand, eight hundred twenty-one".