647740644 has 12 divisors (see below), whose sum is σ = 1511394864. Its totient is φ = 215913544.

The previous prime is 647740637. The next prime is 647740649. The reversal of 647740644 is 446047746.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 647740596 and 647740605.

It is not an unprimeable number, because it can be changed into a prime (647740649) 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 3 ways as a sum of consecutive naturals, for example, 26989182 + ... + 26989205.

It is an arithmetic number, because the mean of its divisors is an integer number (125949572).

Almost surely, 2^647740644 is an apocalyptic number.

It is an amenable number.

647740644 is an abundant number, since it is smaller than the sum of its proper divisors (863654220).

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

647740644 is a wasteful number, since it uses less digits than its factorization.

647740644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53978394 (or 53978392 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 42.

The square root of 647740644 is about 25450.7493799299. The cubic root of 647740644 is about 865.2342773712.

The spelling of 647740644 in words is "six hundred forty-seven million, seven hundred forty thousand, six hundred forty-four".