646553376 has 144 divisors (see below), whose sum is σ = 2173953600. Its totient is φ = 178343424.

The previous prime is 646553371. The next prime is 646553381. The reversal of 646553376 is 673355646.

646553376 is a `hidden beast` number, since 6 + 46 + 5 + 533 + 76 = 666.

It is an interprime number because it is at equal distance from previous prime (646553371) and next prime (646553381).

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (646553371) by changing a digit.

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, 52935 + ... + 63993.

It is an arithmetic number, because the mean of its divisors is an integer number (15096900).

Almost surely, 2^646553376 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 646553376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1086976800).

646553376 is an abundant number, since it is smaller than the sum of its proper divisors (1527400224).

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

646553376 is a wasteful number, since it uses less digits than its factorization.

646553376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11111 (or 11100 counting only the distinct ones).

The product of its digits is 1360800, while the sum is 45.

The square root of 646553376 is about 25427.4138677137. The cubic root of 646553376 is about 864.7053139881.

The spelling of 646553376 in words is "six hundred forty-six million, five hundred fifty-three thousand, three hundred seventy-six".