646768128 has 240 divisors, whose sum is σ = 1929590784. Its totient is φ = 192184320.

The previous prime is 646768099. The next prime is 646768147. The reversal of 646768128 is 821867646.

It is a super-2 number, since 2×646768128² = 836618022793248768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

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, 13761001 + ... + 13761047.

Almost surely, 2^646768128 is an apocalyptic number.

646768128 is a gapful number since it is divisible by the number (68) 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 646768128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964795392).

646768128 is an abundant number, since it is smaller than the sum of its proper divisors (1282822656).

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

646768128 is a wasteful number, since it uses less digits than its factorization.

646768128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 100 counting only the distinct ones).

The product of its digits is 774144, while the sum is 48.

The square root of 646768128 is about 25431.6363610366. The cubic root of 646768128 is about 864.8010403666.

The spelling of 646768128 in words is "six hundred forty-six million, seven hundred sixty-eight thousand, one hundred twenty-eight".