646115511605 has 4 divisors (see below), whose sum is σ = 775338613932. Its totient is φ = 516892409280.

The previous prime is 646115511593. The next prime is 646115511619. The reversal of 646115511605 is 506115511646.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 259994950609 + 386120560996 = 509897^2 + 621386^2 .

It is not a de Polignac number, because 646115511605 - 2⁴ = 646115511589 is a prime.

It is a super-3 number, since 3×646115511605³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64611551156 + ... + 64611551165.

It is an arithmetic number, because the mean of its divisors is an integer number (193834653483).

Almost surely, 2^646115511605 is an apocalyptic number.

It is an amenable number.

646115511605 is a deficient number, since it is larger than the sum of its proper divisors (129223102327).

646115511605 is a wasteful number, since it uses less digits than its factorization.

646115511605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129223102326.

The product of its (nonzero) digits is 108000, while the sum is 41.

Adding to 646115511605 its sum of digits (41), we get a palindrome (646115511646).

The spelling of 646115511605 in words is "six hundred forty-six billion, one hundred fifteen million, five hundred eleven thousand, six hundred five".