647445820 has 36 divisors (see below), whose sum is σ = 1581620040. Its totient is φ = 221981088.

The previous prime is 647445787. The next prime is 647445823. The reversal of 647445820 is 28544746.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647445823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 329350 + ... + 331309.

It is an arithmetic number, because the mean of its divisors is an integer number (43933890).

Almost surely, 2^647445820 is an apocalyptic number.

It is an amenable number.

647445820 is an abundant number, since it is smaller than the sum of its proper divisors (934174220).

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

647445820 is a wasteful number, since it uses less digits than its factorization.

647445820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 660682 (or 660673 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 40.

The square root of 647445820 is about 25444.9566712148. The cubic root of 647445820 is about 865.1029848315.

The spelling of 647445820 in words is "six hundred forty-seven million, four hundred forty-five thousand, eight hundred twenty".