161898580 has 12 divisors (see below), whose sum is σ = 339987060. Its totient is φ = 64759424.

The previous prime is 161898559. The next prime is 161898617. The reversal of 161898580 is 85898161.

It can be written as a sum of positive squares in 2 ways, for example, as 17994564 + 143904016 = 4242^2 + 11996^2 .

It is a super-2 number, since 2×161898580² = 52422300412032800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161898580.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4047445 + ... + 4047484.

It is an arithmetic number, because the mean of its divisors is an integer number (28332255).

Almost surely, 2^161898580 is an apocalyptic number.

161898580 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161898580 is an abundant number, since it is smaller than the sum of its proper divisors (178088480).

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

161898580 is a wasteful number, since it uses less digits than its factorization.

161898580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8094938 (or 8094936 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 46.

The square root of 161898580 is about 12723.9372837184. The cubic root of 161898580 is about 545.0223933789.

The spelling of 161898580 in words is "one hundred sixty-one million, eight hundred ninety-eight thousand, five hundred eighty".