161655405 has 16 divisors (see below), whose sum is σ = 265640064. Its totient is φ = 83885760.

The previous prime is 161655391. The next prime is 161655407. The reversal of 161655405 is 504556161.

161655405 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 161655405 - 2⁸ = 161655149 is a prime.

It is a super-2 number, since 2×161655405² = 52264939931428050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161655407) 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, 145081 + ... + 146190.

It is an arithmetic number, because the mean of its divisors is an integer number (16602504).

Almost surely, 2^161655405 is an apocalyptic number.

161655405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161655405 is a deficient number, since it is larger than the sum of its proper divisors (103984659).

161655405 is a wasteful number, since it uses less digits than its factorization.

161655405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291316.

The product of its (nonzero) digits is 18000, while the sum is 33.

The square root of 161655405 is about 12714.3778848987. The cubic root of 161655405 is about 544.7493783569.

The spelling of 161655405 in words is "one hundred sixty-one million, six hundred fifty-five thousand, four hundred five".