646578238057 has 4 divisors (see below), whose sum is σ = 647091804240. Its totient is φ = 646064671876.

The previous prime is 646578238049. The next prime is 646578238063. The reversal of 646578238057 is 750832875646.

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 646578238057 - 2³ = 646578238049 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 646578237986 and 646578238004.

It is not an unprimeable number, because it can be changed into a prime (646578233057) 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, 256781203 + ... + 256783720.

It is an arithmetic number, because the mean of its divisors is an integer number (161772951060).

Almost surely, 2^646578238057 is an apocalyptic number.

It is an amenable number.

646578238057 is a deficient number, since it is larger than the sum of its proper divisors (513566183).

646578238057 is a wasteful number, since it uses less digits than its factorization.

646578238057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513566182.

The product of its (nonzero) digits is 67737600, while the sum is 61.

The spelling of 646578238057 in words is "six hundred forty-six billion, five hundred seventy-eight million, two hundred thirty-eight thousand, fifty-seven".