3865404661 has 4 divisors (see below), whose sum is σ = 3865581900. Its totient is φ = 3865227424.

The previous prime is 3865404659. The next prime is 3865404671. The reversal of 3865404661 is 1664045683.

It is a happy number.

3865404661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1664045683 = 31 ⋅53678893.

It can be written as a sum of positive squares in 2 ways, for example, as 3458616100 + 406788561 = 58810^2 + 20169^2 .

It is a cyclic number.

It is not a de Polignac number, because 3865404661 - 2¹ = 3865404659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3865404671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50416 + ... + 101353.

It is an arithmetic number, because the mean of its divisors is an integer number (966395475).

Almost surely, 2^3865404661 is an apocalyptic number.

It is an amenable number.

3865404661 is a deficient number, since it is larger than the sum of its proper divisors (177239).

3865404661 is a wasteful number, since it uses less digits than its factorization.

3865404661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177238.

The product of its (nonzero) digits is 414720, while the sum is 43.

The square root of 3865404661 is about 62172.3786017553. The cubic root of 3865404661 is about 1569.3927981764.

The spelling of 3865404661 in words is "three billion, eight hundred sixty-five million, four hundred four thousand, six hundred sixty-one".