256428405 has 24 divisors (see below), whose sum is σ = 445715712. Its totient is φ = 136380384.

The previous prime is 256428397. The next prime is 256428407. The reversal of 256428405 is 504824652.

It is a happy number.

256428405 is a `hidden beast` number, since 2 + 5 + 642 + 8 + 4 + 0 + 5 = 666.

It is not a de Polignac number, because 256428405 - 2³ = 256428397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256428405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256428407) 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, 8752 + ... + 24278.

It is an arithmetic number, because the mean of its divisors is an integer number (18571488).

Almost surely, 2^256428405 is an apocalyptic number.

It is an amenable number.

256428405 is a deficient number, since it is larger than the sum of its proper divisors (189287307).

256428405 is a wasteful number, since it uses less digits than its factorization.

256428405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15905 (or 15902 counting only the distinct ones).

The product of its (nonzero) digits is 76800, while the sum is 36.

The square root of 256428405 is about 16013.3820600147. The cubic root of 256428405 is about 635.3144163888.

The spelling of 256428405 in words is "two hundred fifty-six million, four hundred twenty-eight thousand, four hundred five".