666986965887 has 16 divisors (see below), whose sum is σ = 1001458437120. Its totient is φ = 391194700800.

The previous prime is 666986965837. The next prime is 666986965891. The reversal of 666986965887 is 788569689666.

It is a happy number.

It is not a de Polignac number, because 666986965887 - 2⁷ = 666986965759 is a prime.

It is a super-2 number, since 2×666986965887² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666986965837) 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, 325994562 + ... + 325996607.

It is an arithmetic number, because the mean of its divisors is an integer number (62591152320).

Almost surely, 2^666986965887 is an apocalyptic number.

666986965887 is a deficient number, since it is larger than the sum of its proper divisors (334471471233).

666986965887 is a wasteful number, since it uses less digits than its factorization.

666986965887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651991214.

The product of its digits is 11287019520, while the sum is 84.

The spelling of 666986965887 in words is "six hundred sixty-six billion, nine hundred eighty-six million, nine hundred sixty-five thousand, eight hundred eighty-seven".