1661338667 has 2 divisors, whose sum is σ = 1661338668. Its totient is φ = 1661338666.

The previous prime is 1661338661. The next prime is 1661338699. The reversal of 1661338667 is 7668331661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1661338667 - 2¹⁴ = 1661322283 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661338661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830669333 + 830669334.

It is an arithmetic number, because the mean of its divisors is an integer number (830669334).

Almost surely, 2^1661338667 is an apocalyptic number.

1661338667 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661338667 is an equidigital number, since it uses as much as digits as its factorization.

1661338667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 47.

The square root of 1661338667 is about 40759.5224088801. The cubic root of 1661338667 is about 1184.3663443899.

The spelling of 1661338667 in words is "one billion, six hundred sixty-one million, three hundred thirty-eight thousand, six hundred sixty-seven".