161538819 has 16 divisors (see below), whose sum is σ = 233335200. Its totient is φ = 99404448.

The previous prime is 161538791. The next prime is 161538829. The reversal of 161538819 is 918835161.

It is not a de Polignac number, because 161538819 - 2⁷ = 161538691 is a prime.

It is a super-2 number, since 2×161538819² = 52189580087829522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161538829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5664 + ... + 18845.

It is an arithmetic number, because the mean of its divisors is an integer number (14583450).

Almost surely, 2^161538819 is an apocalyptic number.

161538819 is a deficient number, since it is larger than the sum of its proper divisors (71796381).

161538819 is an equidigital number, since it uses as much as digits as its factorization.

161538819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24551 (or 24525 counting only the distinct ones).

The product of its digits is 51840, while the sum is 42.

The square root of 161538819 is about 12709.7922484988. The cubic root of 161538819 is about 544.6183889745.

The spelling of 161538819 in words is "one hundred sixty-one million, five hundred thirty-eight thousand, eight hundred nineteen".