646777889673 has 4 divisors (see below), whose sum is σ = 862370519568. Its totient is φ = 431185259780.

The previous prime is 646777889671. The next prime is 646777889717. The reversal of 646777889673 is 376988777646.

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 646777889673 - 2¹ = 646777889671 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646777889671) 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, 107796314943 + ... + 107796314948.

It is an arithmetic number, because the mean of its divisors is an integer number (215592629892).

Almost surely, 2^646777889673 is an apocalyptic number.

It is an amenable number.

646777889673 is a deficient number, since it is larger than the sum of its proper divisors (215592629895).

646777889673 is a wasteful number, since it uses less digits than its factorization.

646777889673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215592629894.

The product of its digits is 3584673792, while the sum is 78.

The spelling of 646777889673 in words is "six hundred forty-six billion, seven hundred seventy-seven million, eight hundred eighty-nine thousand, six hundred seventy-three".