161387591 has 2 divisors, whose sum is σ = 161387592. Its totient is φ = 161387590.

The previous prime is 161387561. The next prime is 161387609. The reversal of 161387591 is 195783161.

161387591 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161387591 - 2¹⁴ = 161371207 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161387561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80693795 + 80693796.

It is an arithmetic number, because the mean of its divisors is an integer number (80693796).

Almost surely, 2^161387591 is an apocalyptic number.

161387591 is a deficient number, since it is larger than the sum of its proper divisors (1).

161387591 is an equidigital number, since it uses as much as digits as its factorization.

161387591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 41.

The square root of 161387591 is about 12703.8415843398. The cubic root of 161387591 is about 544.4483838841.

The spelling of 161387591 in words is "one hundred sixty-one million, three hundred eighty-seven thousand, five hundred ninety-one".