646236864 has 168 divisors, whose sum is σ = 2279964960. Its totient is φ = 170422272.

The previous prime is 646236863. The next prime is 646236889. The reversal of 646236864 is 468632646.

It is a tau number, because it is divible by the number of its divisors (168).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (646236863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 46252 + ... + 58580.

It is an arithmetic number, because the mean of its divisors is an integer number (13571220).

Almost surely, 2^646236864 is an apocalyptic number.

646236864 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646236864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1139982480).

646236864 is an abundant number, since it is smaller than the sum of its proper divisors (1633728096).

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

646236864 is a wasteful number, since it uses less digits than its factorization.

646236864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12367 (or 12354 counting only the distinct ones).

The product of its digits is 995328, while the sum is 45.

The square root of 646236864 is about 25421.1892719440. The cubic root of 646236864 is about 864.5641891194.

The spelling of 646236864 in words is "six hundred forty-six million, two hundred thirty-six thousand, eight hundred sixty-four".