664646242 has 12 divisors (see below), whose sum is σ = 1079559090. Its totient is φ = 306759648.

The previous prime is 664646233. The next prime is 664646267. The reversal of 664646242 is 242646466.

It can be written as a sum of positive squares in 3 ways, for example, as 103856481 + 560789761 = 10191^2 + 23681^2 .

It is a junction number, because it is equal to n+sod(n) for n = 664646195 and 664646204.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 982867 + ... + 983542.

Almost surely, 2^664646242 is an apocalyptic number.

664646242 is a deficient number, since it is larger than the sum of its proper divisors (414912848).

664646242 is a wasteful number, since it uses less digits than its factorization.

664646242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1966437 (or 1966424 counting only the distinct ones).

The product of its digits is 331776, while the sum is 40.

The square root of 664646242 is about 25780.7339305924. The cubic root of 664646242 is about 872.6970699584.

The spelling of 664646242 in words is "six hundred sixty-four million, six hundred forty-six thousand, two hundred forty-two".