161951693 has 2 divisors, whose sum is σ = 161951694. Its totient is φ = 161951692.

The previous prime is 161951633. The next prime is 161951731. The reversal of 161951693 is 396159161.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150749284 + 11202409 = 12278^2 + 3347^2 .

It is a cyclic number.

It is not a de Polignac number, because 161951693 - 2¹⁶ = 161886157 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_9077675 and since 161951693 and 9077675 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 161951693.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161951633) 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 as a sum of consecutive naturals, namely, 80975846 + 80975847.

It is an arithmetic number, because the mean of its divisors is an integer number (80975847).

Almost surely, 2^161951693 is an apocalyptic number.

It is an amenable number.

161951693 is a deficient number, since it is larger than the sum of its proper divisors (1).

161951693 is an equidigital number, since it uses as much as digits as its factorization.

161951693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43740, while the sum is 41.

The square root of 161951693 is about 12726.0242416868. The cubic root of 161951693 is about 545.0819874972.

The spelling of 161951693 in words is "one hundred sixty-one million, nine hundred fifty-one thousand, six hundred ninety-three".