161818815 has 16 divisors (see below), whose sum is σ = 259417728. Its totient is φ = 86134176.

The previous prime is 161818807. The next prime is 161818819. The reversal of 161818815 is 518818161.

It is not a de Polignac number, because 161818815 - 2³ = 161818807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161818819) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2469 + ... + 18158.

It is an arithmetic number, because the mean of its divisors is an integer number (16213608).

Almost surely, 2^161818815 is an apocalyptic number.

161818815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

161818815 is a deficient number, since it is larger than the sum of its proper divisors (97598913).

161818815 is a wasteful number, since it uses less digits than its factorization.

161818815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21158.

The product of its digits is 15360, while the sum is 39.

The square root of 161818815 is about 12720.8024511035. The cubic root of 161818815 is about 544.9328705579.

The spelling of 161818815 in words is "one hundred sixty-one million, eight hundred eighteen thousand, eight hundred fifteen".