664860877021 has 4 divisors (see below), whose sum is σ = 725302774944. Its totient is φ = 604418979100.

The previous prime is 664860877007. The next prime is 664860877027. The reversal of 664860877021 is 120778068466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 664860877021 - 2¹¹ = 664860874973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664860877027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30220948945 + ... + 30220948966.

It is an arithmetic number, because the mean of its divisors is an integer number (181325693736).

Almost surely, 2^664860877021 is an apocalyptic number.

It is an amenable number.

664860877021 is a deficient number, since it is larger than the sum of its proper divisors (60441897923).

664860877021 is a wasteful number, since it uses less digits than its factorization.

664860877021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60441897922.

The product of its (nonzero) digits is 5419008, while the sum is 55.

The spelling of 664860877021 in words is "six hundred sixty-four billion, eight hundred sixty million, eight hundred seventy-seven thousand, twenty-one".