3961809866 has 24 divisors (see below), whose sum is σ = 6834237984. Its totient is φ = 1687343400.

The previous prime is 3961809847. The next prime is 3961809923. The reversal of 3961809866 is 6689081693.

3961809866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 366641 + ... + 377291.

It is an arithmetic number, because the mean of its divisors is an integer number (284759916).

Almost surely, 2^3961809866 is an apocalyptic number.

3961809866 is a deficient number, since it is larger than the sum of its proper divisors (2872428118).

3961809866 is a wasteful number, since it uses less digits than its factorization.

3961809866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10986 (or 10823 counting only the distinct ones).

The product of its (nonzero) digits is 3359232, while the sum is 56.

The square root of 3961809866 is about 62942.9095768538. The cubic root of 3961809866 is about 1582.3329667713.

The spelling of 3961809866 in words is "three billion, nine hundred sixty-one million, eight hundred nine thousand, eight hundred sixty-six".