665510642 has 4 divisors (see below), whose sum is σ = 998265966. Its totient is φ = 332755320.

The previous prime is 665510639. The next prime is 665510653. The reversal of 665510642 is 246015566.

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., 473106001 + 192404641 = 21751^2 + 13871^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 166377659 + ... + 166377662.

Almost surely, 2^665510642 is an apocalyptic number.

665510642 is a deficient number, since it is larger than the sum of its proper divisors (332755324).

665510642 is a wasteful number, since it uses less digits than its factorization.

665510642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332755323.

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 665510642 is about 25797.4929402064. The cubic root of 665510642 is about 873.0752323103.

The spelling of 665510642 in words is "six hundred sixty-five million, five hundred ten thousand, six hundred forty-two".