666742071 has 16 divisors (see below), whose sum is σ = 905788800. Its totient is φ = 436167840.

The previous prime is 666742061. The next prime is 666742073. The reversal of 666742071 is 170247666.

It is not a de Polignac number, because 666742071 - 2⁶ = 666742007 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666742073) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28116 + ... + 46086.

It is an arithmetic number, because the mean of its divisors is an integer number (56611800).

Almost surely, 2^666742071 is an apocalyptic number.

666742071 is a deficient number, since it is larger than the sum of its proper divisors (239046729).

666742071 is a wasteful number, since it uses less digits than its factorization.

666742071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18206.

The product of its (nonzero) digits is 84672, while the sum is 39.

The square root of 666742071 is about 25821.3491320651. The cubic root of 666742071 is about 873.6133993709.

The spelling of 666742071 in words is "six hundred sixty-six million, seven hundred forty-two thousand, seventy-one".