161898277 has 4 divisors (see below), whose sum is σ = 161924076. Its totient is φ = 161872480.

The previous prime is 161898251. The next prime is 161898281. The reversal of 161898277 is 772898161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 50680161 + 111218116 = 7119^2 + 10546^2 .

It is a cyclic number.

It is not a de Polignac number, because 161898277 - 2²³ = 153509669 is a prime.

It is a super-2 number, since 2×161898277² = 52422104191137458, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161898277.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161808277) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3273 + ... + 18289.

It is an arithmetic number, because the mean of its divisors is an integer number (40481019).

Almost surely, 2^161898277 is an apocalyptic number.

It is an amenable number.

161898277 is a deficient number, since it is larger than the sum of its proper divisors (25799).

161898277 is a wasteful number, since it uses less digits than its factorization.

161898277 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25798.

The product of its digits is 338688, while the sum is 49.

The square root of 161898277 is about 12723.9253770210. The cubic root of 161898277 is about 545.0220533679.

The spelling of 161898277 in words is "one hundred sixty-one million, eight hundred ninety-eight thousand, two hundred seventy-seven".