664040642 has 4 divisors (see below), whose sum is σ = 996060966. Its totient is φ = 332020320.

The previous prime is 664040623. The next prime is 664040687. The reversal of 664040642 is 246040466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 590441401 + 73599241 = 24299^2 + 8579^2 .

It is a junction number, because it is equal to n+sod(n) for n = 664040599 and 664040608.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166010159 + ... + 166010162.

Almost surely, 2^664040642 is an apocalyptic number.

664040642 is a deficient number, since it is larger than the sum of its proper divisors (332020324).

664040642 is a wasteful number, since it uses less digits than its factorization.

664040642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332020323.

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 664040642 is about 25768.9860491250. The cubic root of 664040642 is about 872.4319334535.

The spelling of 664040642 in words is "six hundred sixty-four million, forty thousand, six hundred forty-two".