256205421 has 24 divisors (see below), whose sum is σ = 385991424. Its totient is φ = 163572480.

The previous prime is 256205407. The next prime is 256205449. The reversal of 256205421 is 124502652.

It is not a de Polignac number, because 256205421 - 2⁶ = 256205357 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256205471) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22330 + ... + 31796.

It is an arithmetic number, because the mean of its divisors is an integer number (16082976).

Almost surely, 2^256205421 is an apocalyptic number.

It is an amenable number.

256205421 is a deficient number, since it is larger than the sum of its proper divisors (129786003).

256205421 is a wasteful number, since it uses less digits than its factorization.

256205421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9601 (or 9598 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 256205421 is about 16006.4181189921. The cubic root of 256205421 is about 635.1302115844.

The spelling of 256205421 in words is "two hundred fifty-six million, two hundred five thousand, four hundred twenty-one".