256400013 has 16 divisors (see below), whose sum is σ = 351869760. Its totient is φ = 165978624.

The previous prime is 256400009. The next prime is 256400029. The reversal of 256400013 is 310004652.

It is a happy number.

256400013 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 256400013 - 2² = 256400009 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256420013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16573 + ... + 28061.

It is an arithmetic number, because the mean of its divisors is an integer number (21991860).

Almost surely, 2^256400013 is an apocalyptic number.

It is an amenable number.

256400013 is a deficient number, since it is larger than the sum of its proper divisors (95469747).

256400013 is a wasteful number, since it uses less digits than its factorization.

256400013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11708.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 256400013 is about 16012.4955269315. The cubic root of 256400013 is about 635.2909679819.

Adding to 256400013 its reverse (310004652), we get a palindrome (566404665).

The spelling of 256400013 in words is "two hundred fifty-six million, four hundred thousand, thirteen".