256136909566 has 8 divisors (see below), whose sum is σ = 385046077680. Its totient is φ = 127788217008.

The previous prime is 256136909521. The next prime is 256136909569. The reversal of 256136909566 is 665909631652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×256136909566² (a number of 24 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256136909566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256136909569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140117746 + ... + 140119573.

It is an arithmetic number, because the mean of its divisors is an integer number (48130759710).

Almost surely, 2^256136909566 is an apocalyptic number.

256136909566 is a deficient number, since it is larger than the sum of its proper divisors (128909168114).

256136909566 is a wasteful number, since it uses less digits than its factorization.

256136909566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280237778.

The product of its (nonzero) digits is 15746400, while the sum is 58.

The spelling of 256136909566 in words is "two hundred fifty-six billion, one hundred thirty-six million, nine hundred nine thousand, five hundred sixty-six".