2556667681 has 8 divisors (see below), whose sum is σ = 2639844864. Its totient is φ = 2473534560.

The previous prime is 2556667679. The next prime is 2556667717. The reversal of 2556667681 is 1867666552.

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 2556667681 - 2¹ = 2556667679 is a prime.

It is a super-2 number, since 2×2556667681² = 13073099262139835522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2556667661) 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, 139980 + ... + 157186.

It is an arithmetic number, because the mean of its divisors is an integer number (329980608).

Almost surely, 2^2556667681 is an apocalyptic number.

It is an amenable number.

2556667681 is a deficient number, since it is larger than the sum of its proper divisors (83177183).

2556667681 is a wasteful number, since it uses less digits than its factorization.

2556667681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22031.

The product of its digits is 3628800, while the sum is 52.

The square root of 2556667681 is about 50563.5014709227. The cubic root of 2556667681 is about 1367.3869386388.

The spelling of 2556667681 in words is "two billion, five hundred fifty-six million, six hundred sixty-seven thousand, six hundred eighty-one".