647221248 has 156 divisors (see below), whose sum is σ = 1899230788. Its totient is φ = 212336640.

The previous prime is 647221243. The next prime is 647221249. The reversal of 647221248 is 842122746.

647221248 is a `hidden beast` number, since 647 + 2 + 2 + 1 + 2 + 4 + 8 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 107495424 + 539725824 = 10368^2 + 23232^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647221243) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3575718 + ... + 3575898.

Almost surely, 2^647221248 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 647221248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (949615394).

647221248 is an abundant number, since it is smaller than the sum of its proper divisors (1252009540).

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

647221248 is a wasteful number, since it uses less digits than its factorization.

647221248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308 (or 283 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 647221248 is about 25440.5433904231. The cubic root of 647221248 is about 865.0029505284.

The spelling of 647221248 in words is "six hundred forty-seven million, two hundred twenty-one thousand, two hundred forty-eight".