666655660642 has 32 divisors (see below), whose sum is σ = 1042124018544. Its totient is φ = 319572556800.

The previous prime is 666655660597. The next prime is 666655660651. The reversal of 666655660642 is 246066556666.

666655660642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 59629244481 + 607026416161 = 244191^2 + 779119^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5426448 + ... + 5547940.

Almost surely, 2^666655660642 is an apocalyptic number.

666655660642 is a deficient number, since it is larger than the sum of its proper divisors (375468357902).

666655660642 is a wasteful number, since it uses less digits than its factorization.

666655660642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122694.

The product of its (nonzero) digits is 55987200, while the sum is 58.

The spelling of 666655660642 in words is "six hundred sixty-six billion, six hundred fifty-five million, six hundred sixty thousand, six hundred forty-two".