1866546456681 has 16 divisors (see below), whose sum is σ = 2635244302464. Its totient is φ = 1171113118464.

The previous prime is 1866546456661. The next prime is 1866546456707.

It is a happy number.

1866546456681 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1866546456681 - 2²¹ = 1866544359529 is a prime.

It is a super-2 number, since 2×1866546456681² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1866546456611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 314676 + ... + 1957578.

It is an arithmetic number, because the mean of its divisors is an integer number (164702768904).

Almost surely, 2^{1866546456681} is an apocalyptic number.

It is an amenable number.

1866546456681 is a deficient number, since it is larger than the sum of its proper divisors (768697845783).

1866546456681 is a wasteful number, since it uses less digits than its factorization.

1866546456681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1665200.

The product of its digits is 199065600, while the sum is 66.

The spelling of 1866546456681 in words is "one trillion, eight hundred sixty-six billion, five hundred forty-six million, four hundred fifty-six thousand, six hundred eighty-one".