646538368 has 128 divisors (see below), whose sum is σ = 1530587520. Its totient is φ = 266305536.

The previous prime is 646538357. The next prime is 646538413. The reversal of 646538368 is 863835646.

It is a tau number, because it is divible by the number of its divisors (128).

It is a super-2 number, since 2×646538368² = 836023722592206848, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3737130 + ... + 3737302.

It is an arithmetic number, because the mean of its divisors is an integer number (11957715).

Almost surely, 2^646538368 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 646538368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (765293760).

646538368 is an abundant number, since it is smaller than the sum of its proper divisors (884049152).

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

646538368 is a wasteful number, since it uses less digits than its factorization.

646538368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 322 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 49.

The square root of 646538368 is about 25427.1187514433. The cubic root of 646538368 is about 864.6986233325.

The spelling of 646538368 in words is "six hundred forty-six million, five hundred thirty-eight thousand, three hundred sixty-eight".