646989984 has 48 divisors (see below), whose sum is σ = 1887056640. Its totient is φ = 215663040.

The previous prime is 646989979. The next prime is 646990031. The reversal of 646989984 is 489989646.

646989984 is a `hidden beast` number, since 6 + 469 + 8 + 99 + 84 = 666.

It is a tau number, because it is divible by the number of its divisors (48).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 373552 + ... + 375279.

It is an arithmetic number, because the mean of its divisors is an integer number (39313680).

Almost surely, 2^646989984 is an apocalyptic number.

It is an amenable number.

646989984 is an abundant number, since it is smaller than the sum of its proper divisors (1240066656).

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

646989984 is a wasteful number, since it uses less digits than its factorization.

646989984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 748850 (or 748836 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 63.

The square root of 646989984 is about 25435.9977983959. The cubic root of 646989984 is about 864.8999111252.

The spelling of 646989984 in words is "six hundred forty-six million, nine hundred eighty-nine thousand, nine hundred eighty-four".