256502071721421 has 8 divisors (see below), whose sum is σ = 380003069216960. Its totient is φ = 171001381147596.

The previous prime is 256502071721369. The next prime is 256502071721443. The reversal of 256502071721421 is 124127170205652.

It is a happy number.

256502071721421 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 0 + 207 + 17 + 2 + 1 + 421 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-256502071721421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256502071721461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4750038365185 + ... + 4750038365238.

It is an arithmetic number, because the mean of its divisors is an integer number (47500383652120).

Almost surely, 2^{256502071721421} is an apocalyptic number.

It is an amenable number.

256502071721421 is a deficient number, since it is larger than the sum of its proper divisors (123500997495539).

256502071721421 is an equidigital number, since it uses as much as digits as its factorization.

256502071721421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9500076730432 (or 9500076730426 counting only the distinct ones).

The product of its (nonzero) digits is 470400, while the sum is 45.

The spelling of 256502071721421 in words is "two hundred fifty-six trillion, five hundred two billion, seventy-one million, seven hundred twenty-one thousand, four hundred twenty-one".