161609819 has 8 divisors (see below), whose sum is σ = 184847328. Its totient is φ = 138409920.

The previous prime is 161609771. The next prime is 161609863. The reversal of 161609819 is 918906161.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161609819 - 2¹⁶ = 161544283 is a prime.

It is a super-2 number, since 2×161609819² = 52235467194425522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161609869) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 509 + ... + 17985.

It is an arithmetic number, because the mean of its divisors is an integer number (23105916).

Almost surely, 2^161609819 is an apocalyptic number.

161609819 is a deficient number, since it is larger than the sum of its proper divisors (23237509).

161609819 is a wasteful number, since it uses less digits than its factorization.

161609819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18805.

The product of its (nonzero) digits is 23328, while the sum is 41.

The square root of 161609819 is about 12712.5850636289. The cubic root of 161609819 is about 544.6981680272.

The spelling of 161609819 in words is "one hundred sixty-one million, six hundred nine thousand, eight hundred nineteen".