161595156121 has 9 divisors (see below), whose sum is σ = 187981312149. Its totient is φ = 138507721884.

The previous prime is 161595156091. The next prime is 161595156137. The reversal of 161595156121 is 121651595161.

The square root of 161595156121 is 401989.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 161595156121 - 2⁹ = 161595155609 is a prime.

It is a super-2 number, since 2×161595156121² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161596156121) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2785210 + ... + 2842636.

It is an arithmetic number, because the mean of its divisors is an integer number (20886812461).

Almost surely, 2^161595156121 is an apocalyptic number.

161595156121 is the 401989-th square number.

161595156121 is the 200995-th centered octagonal number.

It is an amenable number.

161595156121 is a deficient number, since it is larger than the sum of its proper divisors (26386156028).

161595156121 is an frugal number, since it uses more digits than its factorization.

161595156121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114868 (or 57434 counting only the distinct ones).

The product of its digits is 81000, while the sum is 43.

The spelling of 161595156121 in words is "one hundred sixty-one billion, five hundred ninety-five million, one hundred fifty-six thousand, one hundred twenty-one".