256191553 has 4 divisors (see below), whose sum is σ = 256456368. Its totient is φ = 255926740.

The previous prime is 256191517. The next prime is 256191569. The reversal of 256191553 is 355191652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256191553 is a prime.

It is a super-2 number, since 2×256191553² = 131268223657103618, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256191053) 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, 130951 + ... + 132892.

It is an arithmetic number, because the mean of its divisors is an integer number (64114092).

Almost surely, 2^256191553 is an apocalyptic number.

It is an amenable number.

256191553 is a deficient number, since it is larger than the sum of its proper divisors (264815).

256191553 is an equidigital number, since it uses as much as digits as its factorization.

256191553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264814.

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

The square root of 256191553 is about 16005.9849119009. The cubic root of 256191553 is about 635.1187518416.

Subtracting 256191553 from its reverse (355191652), we obtain a palindrome (99000099).

It can be divided in two parts, 25619 and 1553, that added together give a palindrome (27172).

The spelling of 256191553 in words is "two hundred fifty-six million, one hundred ninety-one thousand, five hundred fifty-three".