161221667 has 2 divisors, whose sum is σ = 161221668. Its totient is φ = 161221666.

The previous prime is 161221603. The next prime is 161221679. The reversal of 161221667 is 766122161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161221667 - 2⁶ = 161221603 is a prime.

It is not a weakly prime, because it can be changed into another prime (161221867) 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, 80610833 + 80610834.

It is an arithmetic number, because the mean of its divisors is an integer number (80610834).

Almost surely, 2^161221667 is an apocalyptic number.

161221667 is a deficient number, since it is larger than the sum of its proper divisors (1).

161221667 is an equidigital number, since it uses as much as digits as its factorization.

161221667 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 32.

The square root of 161221667 is about 12697.3094394049. The cubic root of 161221667 is about 544.2617358492.

The spelling of 161221667 in words is "one hundred sixty-one million, two hundred twenty-one thousand, six hundred sixty-seven".