256820727617816 has 32 divisors (see below), whose sum is σ = 481679844276960. Its totient is φ = 128372770885632.

The previous prime is 256820727617789. The next prime is 256820727617819. The reversal of 256820727617816 is 618716727028652.

It is a super-2 number, since 2×256820727617816² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256820727617819) 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, 1601615741 + ... + 1601776083.

It is an arithmetic number, because the mean of its divisors is an integer number (15052495133655).

Almost surely, 2^{256820727617816} is an apocalyptic number.

It is an amenable number.

256820727617816 is a deficient number, since it is larger than the sum of its proper divisors (224859116659144).

256820727617816 is a wasteful number, since it uses less digits than its factorization.

256820727617816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217715 (or 217711 counting only the distinct ones).

The product of its (nonzero) digits is 189665280, while the sum is 68.

The spelling of 256820727617816 in words is "two hundred fifty-six trillion, eight hundred twenty billion, seven hundred twenty-seven million, six hundred seventeen thousand, eight hundred sixteen".