256421823 has 8 divisors (see below), whose sum is σ = 390738048. Its totient is φ = 146526744.

The previous prime is 256421819. The next prime is 256421827. The reversal of 256421823 is 328124652.

It is an interprime number because it is at equal distance from previous prime (256421819) and next prime (256421827).

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

It is not a de Polignac number, because 256421823 - 2² = 256421819 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256421827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6105261 + ... + 6105302.

It is an arithmetic number, because the mean of its divisors is an integer number (48842256).

Almost surely, 2^256421823 is an apocalyptic number.

256421823 is a deficient number, since it is larger than the sum of its proper divisors (134316225).

256421823 is a wasteful number, since it uses less digits than its factorization.

256421823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12210573.

The product of its digits is 23040, while the sum is 33.

The square root of 256421823 is about 16013.1765430848. The cubic root of 256421823 is about 635.3089805956.

The spelling of 256421823 in words is "two hundred fifty-six million, four hundred twenty-one thousand, eight hundred twenty-three".