256331645 has 8 divisors (see below), whose sum is σ = 308710104. Its totient is φ = 204323904.

The previous prime is 256331629. The next prime is 256331651. The reversal of 256331645 is 546133652.

It can be written as a sum of positive squares in 4 ways, for example, as 395641 + 255936004 = 629^2 + 15998^2 .

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 256331645 - 2⁴ = 256331629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91154 + ... + 93923.

It is an arithmetic number, because the mean of its divisors is an integer number (38588763).

Almost surely, 2^256331645 is an apocalyptic number.

It is an amenable number.

256331645 is a deficient number, since it is larger than the sum of its proper divisors (52378459).

256331645 is a wasteful number, since it uses less digits than its factorization.

256331645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185359.

The product of its digits is 64800, while the sum is 35.

The square root of 256331645 is about 16010.3605518427. The cubic root of 256331645 is about 635.2344970619.

The spelling of 256331645 in words is "two hundred fifty-six million, three hundred thirty-one thousand, six hundred forty-five".