161291805 has 8 divisors (see below), whose sum is σ = 258066912. Its totient is φ = 86022288.

The previous prime is 161291761. The next prime is 161291807. The reversal of 161291805 is 508192161.

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

It is not a de Polignac number, because 161291805 - 2⁸ = 161291549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161291807) 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, 5376379 + ... + 5376408.

It is an arithmetic number, because the mean of its divisors is an integer number (32258364).

Almost surely, 2^161291805 is an apocalyptic number.

161291805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161291805 is a deficient number, since it is larger than the sum of its proper divisors (96775107).

161291805 is a wasteful number, since it uses less digits than its factorization.

161291805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10752795.

The product of its (nonzero) digits is 4320, while the sum is 33.

The square root of 161291805 is about 12700.0710627933. The cubic root of 161291805 is about 544.3406497570.

The spelling of 161291805 in words is "one hundred sixty-one million, two hundred ninety-one thousand, eight hundred five".