256561603 has 4 divisors (see below), whose sum is σ = 271653480. Its totient is φ = 241469728.

The previous prime is 256561601. The next prime is 256561631. The reversal of 256561603 is 306165652.

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 256561603 - 2¹ = 256561601 is a prime.

It is a super-2 number, since 2×256561603² = 131647712267859218, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256561601) 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, 7545913 + ... + 7545946.

It is an arithmetic number, because the mean of its divisors is an integer number (67913370).

Almost surely, 2^256561603 is an apocalyptic number.

256561603 is a deficient number, since it is larger than the sum of its proper divisors (15091877).

256561603 is a wasteful number, since it uses less digits than its factorization.

256561603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15091876.

The product of its (nonzero) digits is 32400, while the sum is 34.

The square root of 256561603 is about 16017.5404791123. The cubic root of 256561603 is about 635.4243989547.

The spelling of 256561603 in words is "two hundred fifty-six million, five hundred sixty-one thousand, six hundred three".