1666912507 has 4 divisors (see below), whose sum is σ = 1795136560. Its totient is φ = 1538688456.

The previous prime is 1666912477. The next prime is 1666912517. The reversal of 1666912507 is 7052196661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7052196661 = 239 ⋅29507099.

It is a cyclic number.

It is not a de Polignac number, because 1666912507 - 2¹⁹ = 1666388219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666912517) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 64112007 + ... + 64112032.

It is an arithmetic number, because the mean of its divisors is an integer number (448784140).

Almost surely, 2^1666912507 is an apocalyptic number.

1666912507 is a deficient number, since it is larger than the sum of its proper divisors (128224053).

1666912507 is a wasteful number, since it uses less digits than its factorization.

1666912507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128224052.

The product of its (nonzero) digits is 136080, while the sum is 43.

The square root of 1666912507 is about 40827.8398522381. The cubic root of 1666912507 is about 1185.6893938197.

The spelling of 1666912507 in words is "one billion, six hundred sixty-six million, nine hundred twelve thousand, five hundred seven".