256553191 has 4 divisors (see below), whose sum is σ = 258907000. Its totient is φ = 254199384.

The previous prime is 256553189. The next prime is 256553197. The reversal of 256553191 is 191355652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256553191 - 2¹ = 256553189 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256553191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256553197) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1176741 + ... + 1176958.

It is an arithmetic number, because the mean of its divisors is an integer number (64726750).

Almost surely, 2^256553191 is an apocalyptic number.

256553191 is a deficient number, since it is larger than the sum of its proper divisors (2353809).

256553191 is a wasteful number, since it uses less digits than its factorization.

256553191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2353808.

The product of its digits is 40500, while the sum is 37.

The square root of 256553191 is about 16017.2778898288. The cubic root of 256553191 is about 635.4174542308.

The spelling of 256553191 in words is "two hundred fifty-six million, five hundred fifty-three thousand, one hundred ninety-one".