256521125653 has 8 divisors (see below), whose sum is σ = 285779503800. Its totient is φ = 228623602368.

The previous prime is 256521125647. The next prime is 256521125681. The reversal of 256521125653 is 356521125652.

It can be written as a sum of positive squares in 4 ways, for example, as 2849744689 + 253671380964 = 53383^2 + 503658^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 256521125653 - 2¹⁷ = 256520994581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256521125353) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 340213318 + ... + 340214071.

It is an arithmetic number, because the mean of its divisors is an integer number (35722437975).

Almost surely, 2^256521125653 is an apocalyptic number.

It is an amenable number.

256521125653 is a deficient number, since it is larger than the sum of its proper divisors (29258378147).

256521125653 is a wasteful number, since it uses less digits than its factorization.

256521125653 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 680427431.

The product of its digits is 540000, while the sum is 43.

Subtracting 256521125653 from its reverse (356521125652), we obtain a palindrome (99999999999).

The spelling of 256521125653 in words is "two hundred fifty-six billion, five hundred twenty-one million, one hundred twenty-five thousand, six hundred fifty-three".