665642042 has 16 divisors (see below), whose sum is σ = 1075916520. Its totient is φ = 307034112.

The previous prime is 665642039. The next prime is 665642053. The reversal of 665642042 is 240246566.

It can be written as a sum of positive squares in 4 ways, for example, as 541074121 + 124567921 = 23261^2 + 11161^2 .

It is a junction number, because it is equal to n+sod(n) for n = 665641993 and 665642011.

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, 42338 + ... + 55890.

Almost surely, 2^665642042 is an apocalyptic number.

665642042 is a deficient number, since it is larger than the sum of its proper divisors (410274478).

665642042 is a wasteful number, since it uses less digits than its factorization.

665642042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15457.

The product of its (nonzero) digits is 69120, while the sum is 35.

The square root of 665642042 is about 25800.0395736131. The cubic root of 665642042 is about 873.1326892107.

The spelling of 665642042 in words is "six hundred sixty-five million, six hundred forty-two thousand, forty-two".