161391010225 has 9 divisors (see below), whose sum is σ = 200127343467. Its totient is φ = 129111201240.

The previous prime is 161391010217. The next prime is 161391010237. The reversal of 161391010225 is 522010193161.

The square root of 161391010225 is 401735.

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

161391010225 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 58100763681 + 103290246544 = 241041^2 + 321388^2 .

It is not a de Polignac number, because 161391010225 - 2³ = 161391010217 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1968502 + ... + 2048848.

Almost surely, 2^161391010225 is an apocalyptic number.

161391010225 is the 401735-th square number.

161391010225 is the 200868-th centered octagonal number.

It is an amenable number.

161391010225 is a deficient number, since it is larger than the sum of its proper divisors (38736333242).

161391010225 is an frugal number, since it uses more digits than its factorization.

161391010225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160704 (or 80352 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 31.

The spelling of 161391010225 in words is "one hundred sixty-one billion, three hundred ninety-one million, ten thousand, two hundred twenty-five".