161611505660 has 96 divisors (see below), whose sum is σ = 383810918400. Its totient is φ = 56621815040.

The previous prime is 161611505659. The next prime is 161611505743. The reversal of 161611505660 is 66505116161.

It is a super-2 number, since 2×161611505660² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3029579 + ... + 3082461.

It is an arithmetic number, because the mean of its divisors is an integer number (3998030400).

Almost surely, 2^161611505660 is an apocalyptic number.

161611505660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161611505660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191905459200).

161611505660 is an abundant number, since it is smaller than the sum of its proper divisors (222199412740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161611505660 is a wasteful number, since it uses less digits than its factorization.

161611505660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53411 (or 53409 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 38.

The spelling of 161611505660 in words is "one hundred sixty-one billion, six hundred eleven million, five hundred five thousand, six hundred sixty".