161966639 has 2 divisors, whose sum is σ = 161966640. Its totient is φ = 161966638.

The previous prime is 161966557. The next prime is 161966647. The reversal of 161966639 is 936669161.

It is a strong prime.

It is an emirp because it is prime and its reverse (936669161) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161966639 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 161966593 and 161966602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161966689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80983319 + 80983320.

It is an arithmetic number, because the mean of its divisors is an integer number (80983320).

Almost surely, 2^161966639 is an apocalyptic number.

161966639 is a deficient number, since it is larger than the sum of its proper divisors (1).

161966639 is an equidigital number, since it uses as much as digits as its factorization.

161966639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 47.

The square root of 161966639 is about 12726.6114500286. The cubic root of 161966639 is about 545.0987549349.

The spelling of 161966639 in words is "one hundred sixty-one million, nine hundred sixty-six thousand, six hundred thirty-nine".