647640450 has 72 divisors (see below), whose sum is σ = 1749244068. Its totient is φ = 171786240.

The previous prime is 647640431. The next prime is 647640481. The reversal of 647640450 is 54046746.

647640450 is a `hidden beast` number, since 6 + 4 + 7 + 640 + 4 + 5 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 101062809 + 546577641 = 10053^2 + 23379^2 .

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 35 ways as a sum of consecutive naturals, for example, 83122 + ... + 90578.

Almost surely, 2^647640450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 647640450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (874622034).

647640450 is an abundant number, since it is smaller than the sum of its proper divisors (1101603618).

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

647640450 is a wasteful number, since it uses less digits than its factorization.

647640450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7668 (or 7660 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 36.

The square root of 647640450 is about 25448.7809138277. The cubic root of 647640450 is about 865.1896629337.

The spelling of 647640450 in words is "six hundred forty-seven million, six hundred forty thousand, four hundred fifty".