256400642 has 8 divisors (see below), whose sum is σ = 401322816. Its totient is φ = 122626372.

The previous prime is 256400609. The next prime is 256400653. The reversal of 256400642 is 246004652.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2786918 + ... + 2787009.

It is an arithmetic number, because the mean of its divisors is an integer number (50165352).

Almost surely, 2^256400642 is an apocalyptic number.

256400642 is a deficient number, since it is larger than the sum of its proper divisors (144922174).

256400642 is a wasteful number, since it uses less digits than its factorization.

256400642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5573952.

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 256400642 is about 16012.5151678304. The cubic root of 256400642 is about 635.2914874797.

The spelling of 256400642 in words is "two hundred fifty-six million, four hundred thousand, six hundred forty-two".