161506729 has 2 divisors, whose sum is σ = 161506730. Its totient is φ = 161506728.

The previous prime is 161506727. The next prime is 161506799. The reversal of 161506729 is 927605161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156875625 + 4631104 = 12525^2 + 2152^2 .

It is a cyclic number.

It is not a de Polignac number, because 161506729 - 2¹ = 161506727 is a prime.

Together with 161506727, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (161506727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80753364 + 80753365.

It is an arithmetic number, because the mean of its divisors is an integer number (80753365).

Almost surely, 2^161506729 is an apocalyptic number.

It is an amenable number.

161506729 is a deficient number, since it is larger than the sum of its proper divisors (1).

161506729 is an equidigital number, since it uses as much as digits as its factorization.

161506729 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 161506729 is about 12708.5297733451. The cubic root of 161506729 is about 544.5823234195.

The spelling of 161506729 in words is "one hundred sixty-one million, five hundred six thousand, seven hundred twenty-nine".