64845547821 has 12 divisors (see below), whose sum is σ = 93670686720. Its totient is φ = 43228105800.

The previous prime is 64845547777. The next prime is 64845547841. The reversal of 64845547821 is 12874554846.

64845547821 is a `hidden beast` number, since 6 + 4 + 8 + 4 + 554 + 7 + 82 + 1 = 666.

It is not a de Polignac number, because 64845547821 - 2⁷ = 64845547693 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64845547841) 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, 3796 + ... + 360146.

It is an arithmetic number, because the mean of its divisors is an integer number (7805890560).

Almost surely, 2^64845547821 is an apocalyptic number.

It is an amenable number.

64845547821 is a deficient number, since it is larger than the sum of its proper divisors (28825138899).

64845547821 is a wasteful number, since it uses less digits than its factorization.

64845547821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376576 (or 376573 counting only the distinct ones).

The product of its digits is 8601600, while the sum is 54.

The spelling of 64845547821 in words is "sixty-four billion, eight hundred forty-five million, five hundred forty-seven thousand, eight hundred twenty-one".