646542612 has 72 divisors (see below), whose sum is σ = 1691143272. Its totient is φ = 208128000.

The previous prime is 646542569. The next prime is 646542643. The reversal of 646542612 is 216245646.

646542612 is a `hidden beast` number, since 646 + 5 + 4 + 2 + 6 + 1 + 2 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2702736 + 643839876 = 1644^2 + 25374^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 146908 + ... + 151244.

It is an arithmetic number, because the mean of its divisors is an integer number (23488101).

Almost surely, 2^646542612 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646542612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (845571636).

646542612 is an abundant number, since it is smaller than the sum of its proper divisors (1044600660).

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

646542612 is a wasteful number, since it uses less digits than its factorization.

646542612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4489 (or 4484 counting only the distinct ones).

The product of its digits is 69120, while the sum is 36.

The square root of 646542612 is about 25427.2022055121. The cubic root of 646542612 is about 864.7005153435.

The spelling of 646542612 in words is "six hundred forty-six million, five hundred forty-two thousand, six hundred twelve".