1665666631 has 2 divisors, whose sum is σ = 1665666632. Its totient is φ = 1665666630.

The previous prime is 1665666589. The next prime is 1665666661. The reversal of 1665666631 is 1366665661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1665666631 - 2⁷ = 1665666503 is a prime.

It is a super-2 number, since 2×1665666631² = 5548890651253780322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1665666661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832833315 + 832833316.

It is an arithmetic number, because the mean of its divisors is an integer number (832833316).

Almost surely, 2^1665666631 is an apocalyptic number.

1665666631 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665666631 is an equidigital number, since it uses as much as digits as its factorization.

1665666631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 46.

The square root of 1665666631 is about 40812.5793230470. The cubic root of 1665666631 is about 1185.3939193744.

The spelling of 1665666631 in words is "one billion, six hundred sixty-five million, six hundred sixty-six thousand, six hundred thirty-one".