161605519 has 4 divisors (see below), whose sum is σ = 171111744. Its totient is φ = 152099296.

The previous prime is 161605517. The next prime is 161605523. The reversal of 161605519 is 915506161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 915506161 = 19927 ⋅45943.

It is a cyclic number.

It is not a de Polignac number, because 161605519 - 2¹ = 161605517 is a prime.

It is a super-2 number, since 2×161605519² = 52232687542518722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161605513) 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, 4753087 + ... + 4753120.

It is an arithmetic number, because the mean of its divisors is an integer number (42777936).

Almost surely, 2^161605519 is an apocalyptic number.

161605519 is a deficient number, since it is larger than the sum of its proper divisors (9506225).

161605519 is an equidigital number, since it uses as much as digits as its factorization.

161605519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9506224.

The product of its (nonzero) digits is 8100, while the sum is 34.

The square root of 161605519 is about 12712.4159387585. The cubic root of 161605519 is about 544.6933370029.

The spelling of 161605519 in words is "one hundred sixty-one million, six hundred five thousand, five hundred nineteen".