1666197664 has 12 divisors (see below), whose sum is σ = 3280326714. Its totient is φ = 833098816.

The previous prime is 1666197661. The next prime is 1666197667. The reversal of 1666197664 is 4667916661.

It is an interprime number because it is at equal distance from previous prime (1666197661) and next prime (1666197667).

It can be written as a sum of positive squares in only one way, i.e., 1482866064 + 183331600 = 38508^2 + 13540^2 .

It is not an unprimeable number, because it can be changed into a prime (1666197661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26034307 + ... + 26034370.

Almost surely, 2^1666197664 is an apocalyptic number.

It is an amenable number.

1666197664 is a deficient number, since it is larger than the sum of its proper divisors (1614129050).

1666197664 is an equidigital number, since it uses as much as digits as its factorization.

1666197664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52068687 (or 52068679 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 52.

The square root of 1666197664 is about 40819.0845561240. The cubic root of 1666197664 is about 1185.5198782336.

The spelling of 1666197664 in words is "one billion, six hundred sixty-six million, one hundred ninety-seven thousand, six hundred sixty-four".