8420405665 has 16 divisors (see below), whose sum is σ = 11572116480. Its totient is φ = 5761926720.

The previous prime is 8420405603. The next prime is 8420405681. The reversal of 8420405665 is 5665040248.

It is not a de Polignac number, because 8420405665 - 2⁷ = 8420405537 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 234366 + ... + 267895.

It is an arithmetic number, because the mean of its divisors is an integer number (723257280).

Almost surely, 2^8420405665 is an apocalyptic number.

It is an amenable number.

8420405665 is a deficient number, since it is larger than the sum of its proper divisors (3151710815).

8420405665 is a wasteful number, since it uses less digits than its factorization.

8420405665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502752.

The product of its (nonzero) digits is 230400, while the sum is 40.

The square root of 8420405665 is about 91762.7684030947. The cubic root of 8420405665 is about 2034.4374336146.

The spelling of 8420405665 in words is "eight billion, four hundred twenty million, four hundred five thousand, six hundred sixty-five".