161247989 has 4 divisors (see below), whose sum is σ = 184283424. Its totient is φ = 138212556.

The previous prime is 161247971. The next prime is 161247991. The reversal of 161247989 is 989742161.

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, and also an emirpimes, since its reverse is a distinct semiprime: 989742161 = 1871 ⋅528991.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161247989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161247589) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11517707 + ... + 11517720.

It is an arithmetic number, because the mean of its divisors is an integer number (46070856).

Almost surely, 2^161247989 is an apocalyptic number.

It is an amenable number.

161247989 is a deficient number, since it is larger than the sum of its proper divisors (23035435).

161247989 is an equidigital number, since it uses as much as digits as its factorization.

161247989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23035434.

The product of its digits is 217728, while the sum is 47.

The square root of 161247989 is about 12698.3459159057. The cubic root of 161247989 is about 544.2913540308.

The spelling of 161247989 in words is "one hundred sixty-one million, two hundred forty-seven thousand, nine hundred eighty-nine".