646808646 has 48 divisors (see below), whose sum is σ = 1436151024. Its totient is φ = 194040000.

The previous prime is 646808633. The next prime is 646808653.

646808646 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×646808646² = 836722849080706632, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 646808595 and 646808604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68916 + ... + 77736.

It is an arithmetic number, because the mean of its divisors is an integer number (29919813).

Almost surely, 2^646808646 is an apocalyptic number.

646808646 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 646808646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (718075512).

646808646 is an abundant number, since it is smaller than the sum of its proper divisors (789342378).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646808646 is a wasteful number, since it uses less digits than its factorization.

646808646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8949 (or 8938 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 48.

The square root of 646808646 is about 25432.4329547922. The cubic root of 646808646 is about 864.8190990162.

The spelling of 646808646 in words is "six hundred forty-six million, eight hundred eight thousand, six hundred forty-six".