256603400605 has 4 divisors (see below), whose sum is σ = 307924080732. Its totient is φ = 205282720480.

The previous prime is 256603400531. The next prime is 256603400609. The reversal of 256603400605 is 506004306652.

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

It can be written as a sum of positive squares in 2 ways, for example, as 202481100441 + 54122300164 = 449979^2 + 232642^2 .

It is not a de Polignac number, because 256603400605 - 2¹³ = 256603392413 is a prime.

It is a super-2 number, since 2×256603400605² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256603400609) 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, 25660340056 + ... + 25660340065.

It is an arithmetic number, because the mean of its divisors is an integer number (76981020183).

Almost surely, 2^256603400605 is an apocalyptic number.

It is an amenable number.

256603400605 is a deficient number, since it is larger than the sum of its proper divisors (51320680127).

256603400605 is an equidigital number, since it uses as much as digits as its factorization.

256603400605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51320680126.

The product of its (nonzero) digits is 129600, while the sum is 37.

The spelling of 256603400605 in words is "two hundred fifty-six billion, six hundred three million, four hundred thousand, six hundred five".