161565665656650 has 48 divisors (see below), whose sum is σ = 400752646180128. Its totient is φ = 43076672632000.

The previous prime is 161565665656621. The next prime is 161565665656663. The reversal of 161565665656650 is 56656566565161.

It is a happy number.

It is a super-2 number, since 2×161565665656650² (a number of 29 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 92946936 + ... + 94669235.

It is an arithmetic number, because the mean of its divisors is an integer number (8349013462086).

Almost surely, 2^{161565665656650} is an apocalyptic number.

161565665656650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161565665656650 is an abundant number, since it is smaller than the sum of its proper divisors (239186980523478).

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

161565665656650 is a wasteful number, since it uses less digits than its factorization.

161565665656650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187621927 (or 187621922 counting only the distinct ones).

The product of its (nonzero) digits is 874800000, while the sum is 69.

The spelling of 161565665656650 in words is "one hundred sixty-one trillion, five hundred sixty-five billion, six hundred sixty-five million, six hundred fifty-six thousand, six hundred fifty".