161611166005605 has 24 divisors (see below), whose sum is σ = 281349278828280. Its totient is φ = 85816234869120.

The previous prime is 161611166005603. The next prime is 161611166005607. The reversal of 161611166005605 is 506500661116161.

161611166005605 is a `hidden beast` number, since 1 + 6 + 1 + 6 + 11 + 16 + 60 + 0 + 560 + 5 = 666.

It is an interprime number because it is at equal distance from previous prime (161611166005603) and next prime (161611166005607).

It can be written as a sum of positive squares in 4 ways, for example, as 7823438355681 + 153787727649924 = 2797041^2 + 12401118^2 .

It is not a de Polignac number, because 161611166005605 - 2¹ = 161611166005603 is a prime.

It is a super-2 number, since 2×161611166005605² (a number of 29 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161611166005603) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7841385426 + ... + 7841406035.

It is an arithmetic number, because the mean of its divisors is an integer number (11722886617845).

Almost surely, 2^{161611166005605} is an apocalyptic number.

161611166005605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161611166005605 is a deficient number, since it is larger than the sum of its proper divisors (119738112822675).

161611166005605 is a wasteful number, since it uses less digits than its factorization.

161611166005605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15682791701 (or 15682791698 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The spelling of 161611166005605 in words is "one hundred sixty-one trillion, six hundred eleven billion, one hundred sixty-six million, five thousand, six hundred five".