161899225 has 6 divisors (see below), whose sum is σ = 200755070. Its totient is φ = 129519360.

The previous prime is 161899217. The next prime is 161899237. The reversal of 161899225 is 522998161.

161899225 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 3 ways, for example, as 23319241 + 138579984 = 4829^2 + 11772^2 .

It is not a de Polignac number, because 161899225 - 2³ = 161899217 is a prime.

It is a super-2 number, since 2×161899225² = 52422718111201250, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3237960 + ... + 3238009.

Almost surely, 2^161899225 is an apocalyptic number.

It is an amenable number.

161899225 is a deficient number, since it is larger than the sum of its proper divisors (38855845).

161899225 is an equidigital number, since it uses as much as digits as its factorization.

161899225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6475979 (or 6475974 counting only the distinct ones).

The product of its digits is 77760, while the sum is 43.

The square root of 161899225 is about 12723.9626296213. The cubic root of 161899225 is about 545.0231171632.

The spelling of 161899225 in words is "one hundred sixty-one million, eight hundred ninety-nine thousand, two hundred twenty-five".