660666642 has 8 divisors (see below), whose sum is σ = 1321333296. Its totient is φ = 220222212.

The previous prime is 660666641. The next prime is 660666649. The reversal of 660666642 is 246666066.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

660666642 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 660666594 and 660666603.

It is not an unprimeable number, because it can be changed into a prime (660666641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55055548 + ... + 55055559.

It is an arithmetic number, because the mean of its divisors is an integer number (165166662).

Almost surely, 2^660666642 is an apocalyptic number.

660666642 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

660666642 is a wasteful number, since it uses less digits than its factorization.

660666642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110111112.

The product of its (nonzero) digits is 373248, while the sum is 42.

The square root of 660666642 is about 25703.4363850439. The cubic root of 660666642 is about 870.9518107301.

The spelling of 660666642 in words is "six hundred sixty million, six hundred sixty-six thousand, six hundred forty-two".