647847720 has 224 divisors, whose sum is σ = 2354977800. Its totient is φ = 159376896.

The previous prime is 647847709. The next prime is 647847721. The reversal of 647847720 is 27748746.

It can be written as a sum of positive squares in 4 ways, for example, as 296735076 + 351112644 = 17226^2 + 18738^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (647847721) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 378226 + ... + 379934.

Almost surely, 2^647847720 is an apocalyptic number.

647847720 is a gapful number since it is divisible by the number (60) 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 647847720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1177488900).

647847720 is an abundant number, since it is smaller than the sum of its proper divisors (1707130080).

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

647847720 is a wasteful number, since it uses less digits than its factorization.

647847720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751 (or 1732 counting only the distinct ones).

The product of its (nonzero) digits is 526848, while the sum is 45.

The square root of 647847720 is about 25452.8528852858. The cubic root of 647847720 is about 865.2819511441.

The spelling of 647847720 in words is "six hundred forty-seven million, eight hundred forty-seven thousand, seven hundred twenty".