256403165646 has 16 divisors (see below), whose sum is σ = 513089515008. Its totient is φ = 85420524600.

The previous prime is 256403165639. The next prime is 256403165651. The reversal of 256403165646 is 646561304652.

It is a super-2 number, since 2×256403165646² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 256403165595 and 256403165604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11787550 + ... + 11809281.

It is an arithmetic number, because the mean of its divisors is an integer number (32068094688).

Almost surely, 2^256403165646 is an apocalyptic number.

256403165646 is an abundant number, since it is smaller than the sum of its proper divisors (256686349362).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256403165646 is a wasteful number, since it uses less digits than its factorization.

256403165646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23598647.

The product of its (nonzero) digits is 3110400, while the sum is 48.

The spelling of 256403165646 in words is "two hundred fifty-six billion, four hundred three million, one hundred sixty-five thousand, six hundred forty-six".