3865866991 has 8 divisors (see below), whose sum is σ = 4425489824. Its totient is φ = 3308083200.

The previous prime is 3865866989. The next prime is 3865867037. The reversal of 3865866991 is 1996685683.

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 3865866991 - 2¹ = 3865866989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865866911) 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, 455250 + ... + 463663.

It is an arithmetic number, because the mean of its divisors is an integer number (553186228).

Almost surely, 2^3865866991 is an apocalyptic number.

3865866991 is a deficient number, since it is larger than the sum of its proper divisors (559622833).

3865866991 is an equidigital number, since it uses as much as digits as its factorization.

3865866991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919521.

The product of its digits is 16796160, while the sum is 61.

The square root of 3865866991 is about 62176.0966208076. The cubic root of 3865866991 is about 1569.4553658771.

The spelling of 3865866991 in words is "three billion, eight hundred sixty-five million, eight hundred sixty-six thousand, nine hundred ninety-one".