647997720 has 96 divisors (see below), whose sum is σ = 1966906800. Its totient is φ = 170785536.

The previous prime is 647997703. The next prime is 647997731. The reversal of 647997720 is 27799746.

It is a happy number.

647997720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1272826 + ... + 1273334.

Almost surely, 2^647997720 is an apocalyptic number.

647997720 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 647997720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (983453400).

647997720 is an abundant number, since it is smaller than the sum of its proper divisors (1318909080).

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

647997720 is a wasteful number, since it uses less digits than its factorization.

647997720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729 (or 622 counting only the distinct ones).

The product of its (nonzero) digits is 1333584, while the sum is 51.

The square root of 647997720 is about 25455.7993392468. The cubic root of 647997720 is about 865.3487272669.

The spelling of 647997720 in words is "six hundred forty-seven million, nine hundred ninety-seven thousand, seven hundred twenty".