256561042 has 8 divisors (see below), whose sum is σ = 407479356. Its totient is φ = 120734592.

The previous prime is 256561013. The next prime is 256561049. The reversal of 256561042 is 240165652.

It can be written as a sum of positive squares in 2 ways, for example, as 221146641 + 35414401 = 14871^2 + 5951^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 256560995 and 256561013.

It is not an unprimeable number, because it can be changed into a prime (256561049) 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, 3772923 + ... + 3772990.

Almost surely, 2^256561042 is an apocalyptic number.

256561042 is a deficient number, since it is larger than the sum of its proper divisors (150918314).

256561042 is a wasteful number, since it uses less digits than its factorization.

256561042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7545932.

The product of its (nonzero) digits is 14400, while the sum is 31.

The square root of 256561042 is about 16017.5229670508. The cubic root of 256561042 is about 635.4239358127.

It can be divided in two parts, 2565610 and 42, that added together give a palindrome (2565652).

The spelling of 256561042 in words is "two hundred fifty-six million, five hundred sixty-one thousand, forty-two".