256521250069 has 8 divisors (see below), whose sum is σ = 293197231040. Its totient is φ = 219852791136.

The previous prime is 256521250033. The next prime is 256521250079. The reversal of 256521250069 is 960052125652.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256521250069 is a prime.

It is a super-2 number, since 2×256521250069² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256521250079) 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 7 ways as a sum of consecutive naturals, for example, 1807239 + ... + 1944004.

It is an arithmetic number, because the mean of its divisors is an integer number (36649653880).

Almost surely, 2^256521250069 is an apocalyptic number.

It is an amenable number.

256521250069 is a deficient number, since it is larger than the sum of its proper divisors (36675980971).

256521250069 is an equidigital number, since it uses as much as digits as its factorization.

256521250069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3761019.

The product of its (nonzero) digits is 324000, while the sum is 43.

It can be divided in two parts, 25652 and 1250069, that added together give a palindrome (1275721).

The spelling of 256521250069 in words is "two hundred fifty-six billion, five hundred twenty-one million, two hundred fifty thousand, sixty-nine".