161858729 has 4 divisors (see below), whose sum is σ = 161986560. Its totient is φ = 161730900.

The previous prime is 161858699. The next prime is 161858731. The reversal of 161858729 is 927858161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161858729 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161858779) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61997 + ... + 64554.

It is an arithmetic number, because the mean of its divisors is an integer number (40496640).

Almost surely, 2^161858729 is an apocalyptic number.

It is an amenable number.

161858729 is a deficient number, since it is larger than the sum of its proper divisors (127831).

161858729 is a wasteful number, since it uses less digits than its factorization.

161858729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127830.

The product of its digits is 241920, while the sum is 47.

The square root of 161858729 is about 12722.3712019419. The cubic root of 161858729 is about 544.9776709983.

The spelling of 161858729 in words is "one hundred sixty-one million, eight hundred fifty-eight thousand, seven hundred twenty-nine".