1666691667 has 8 divisors (see below), whose sum is σ = 2469172880. Its totient is φ = 1111127760.

The previous prime is 1666691659. The next prime is 1666691671. The reversal of 1666691667 is 7661966661.

It is not a de Polignac number, because 1666691667 - 2³ = 1666691659 is a prime.

It is a super-2 number, since 2×1666691667² = 5555722225694477778, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666691617) 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 7 ways as a sum of consecutive naturals, for example, 30864634 + ... + 30864687.

It is an arithmetic number, because the mean of its divisors is an integer number (308646610).

Almost surely, 2^1666691667 is an apocalyptic number.

1666691667 is a deficient number, since it is larger than the sum of its proper divisors (802481213).

1666691667 is an equidigital number, since it uses as much as digits as its factorization.

1666691667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61729330 (or 61729324 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 54.

The square root of 1666691667 is about 40825.1352355384. The cubic root of 1666691667 is about 1185.6370297016.

The spelling of 1666691667 in words is "one billion, six hundred sixty-six million, six hundred ninety-one thousand, six hundred sixty-seven".