161636405 has 8 divisors (see below), whose sum is σ = 221672832. Its totient is φ = 110836368.

The previous prime is 161636389. The next prime is 161636407. The reversal of 161636405 is 504636161.

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 161636405 - 2⁴ = 161636389 is a prime.

It is a super-2 number, since 2×161636405² = 52252654842648050, 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 (161636407) 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 7 ways as a sum of consecutive naturals, for example, 2309057 + ... + 2309126.

It is an arithmetic number, because the mean of its divisors is an integer number (27709104).

Almost surely, 2^161636405 is an apocalyptic number.

It is an amenable number.

161636405 is a deficient number, since it is larger than the sum of its proper divisors (60036427).

161636405 is an equidigital number, since it uses as much as digits as its factorization.

161636405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4618195.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 161636405 is about 12713.6306773478. The cubic root of 161636405 is about 544.7280353368.

The spelling of 161636405 in words is "one hundred sixty-one million, six hundred thirty-six thousand, four hundred five".