256816511 has 8 divisors (see below), whose sum is σ = 300330624. Its totient is φ = 215008920.

The previous prime is 256816477. The next prime is 256816517. The reversal of 256816511 is 115618652.

It is a happy number.

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

It is not a de Polignac number, because 256816511 - 2¹⁰ = 256815487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256816517) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 426305 + ... + 426906.

It is an arithmetic number, because the mean of its divisors is an integer number (37541328).

Almost surely, 2^256816511 is an apocalyptic number.

256816511 is a deficient number, since it is larger than the sum of its proper divisors (43514113).

256816511 is an equidigital number, since it uses as much as digits as its factorization.

256816511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853261.

The product of its digits is 14400, while the sum is 35.

The square root of 256816511 is about 16025.4956553612. The cubic root of 256816511 is about 635.6347722747.

The spelling of 256816511 in words is "two hundred fifty-six million, eight hundred sixteen thousand, five hundred eleven".