161489509 has 32 divisors (see below), whose sum is σ = 182845440. Its totient is φ = 142084800.

The previous prime is 161489507. The next prime is 161489513. The reversal of 161489509 is 905984161.

It is not a de Polignac number, because 161489509 - 2¹ = 161489507 is a prime.

It is a super-2 number, since 2×161489509² = 52157723034122162, which contains 22 as substring.

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161489507) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2044132 + ... + 2044210.

It is an arithmetic number, because the mean of its divisors is an integer number (5713920).

Almost surely, 2^161489509 is an apocalyptic number.

It is an amenable number.

161489509 is a deficient number, since it is larger than the sum of its proper divisors (21355931).

161489509 is a wasteful number, since it uses less digits than its factorization.

161489509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241.

The product of its (nonzero) digits is 77760, while the sum is 43.

The square root of 161489509 is about 12707.8522575611. The cubic root of 161489509 is about 544.5629681043.

The spelling of 161489509 in words is "one hundred sixty-one million, four hundred eighty-nine thousand, five hundred nine".