1866666681 has 64 divisors (see below), whose sum is σ = 3073075200. Its totient is φ = 1110456000.

The previous prime is 1866666677. The next prime is 1866666689.

1866666681 is nontrivially palindromic in base 10.

1866666681 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1866666681 - 2² = 1866666677 is a prime.

It is a super-2 number, since 2×1866666681² = 6968888995911111522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1866666689) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4798435 + ... + 4798823.

It is an arithmetic number, because the mean of its divisors is an integer number (48016800).

Almost surely, 2^1866666681 is an apocalyptic number.

1866666681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1866666681 is a deficient number, since it is larger than the sum of its proper divisors (1206408519).

1866666681 is a wasteful number, since it uses less digits than its factorization.

1866666681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667 (or 661 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 54.

The square root of 1866666681 is about 43204.9381552618. The cubic root of 1866666681 is about 1231.2765034500.

The spelling of 1866666681 in words is "one billion, eight hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-one".