647312977820 has 48 divisors (see below), whose sum is σ = 1377200367648. Its totient is φ = 255533149440.

The previous prime is 647312977819. The next prime is 647312977823. The reversal of 647312977820 is 28779213746.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (647312977823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1354862 + ... + 1769258.

It is an arithmetic number, because the mean of its divisors is an integer number (28691674326).

Almost surely, 2^647312977820 is an apocalyptic number.

It is an amenable number.

647312977820 is an abundant number, since it is smaller than the sum of its proper divisors (729887389828).

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

647312977820 is a wasteful number, since it uses less digits than its factorization.

647312977820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415430 (or 415428 counting only the distinct ones).

The product of its (nonzero) digits is 7112448, while the sum is 56.

The spelling of 647312977820 in words is "six hundred forty-seven billion, three hundred twelve million, nine hundred seventy-seven thousand, eight hundred twenty".