161605551666666 has 16 divisors (see below), whose sum is σ = 323543967509088. Its totient is φ = 53813039859600.

The previous prime is 161605551666661. The next prime is 161605551666667. The reversal of 161605551666666 is 666666155506161.

161605551666666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161605551666666² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161605551666597 and 161605551666606.

It is not an unprimeable number, because it can be changed into a prime (161605551666661) 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, 13869334345 + ... + 13869345996.

It is an arithmetic number, because the mean of its divisors is an integer number (20221497969318).

Almost surely, 2^{161605551666666} is an apocalyptic number.

161605551666666 is an abundant number, since it is smaller than the sum of its proper divisors (161938415842422).

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

161605551666666 is a wasteful number, since it uses less digits than its factorization.

161605551666666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27738681317.

The product of its (nonzero) digits is 209952000, while the sum is 66.

The spelling of 161605551666666 in words is "one hundred sixty-one trillion, six hundred five billion, five hundred fifty-one million, six hundred sixty-six thousand, six hundred sixty-six".