161667090 has 120 divisors (see below), whose sum is σ = 471114468. Its totient is φ = 39761280.

The previous prime is 161667073. The next prime is 161667109. The reversal of 161667090 is 90766161.

It can be written as a sum of positive squares in 6 ways, for example, as 47155689 + 114511401 = 6867^2 + 10701^2 .

It is a super-2 number, since 2×161667090² = 52272495978136200, which contains 22 as substring.

It is a Curzon 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 59 ways as a sum of consecutive naturals, for example, 136300 + ... + 137480.

Almost surely, 2^161667090 is an apocalyptic number.

161667090 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 161667090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (235557234).

161667090 is an abundant number, since it is smaller than the sum of its proper divisors (309447378).

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

161667090 is a wasteful number, since it uses less digits than its factorization.

161667090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226 (or 1204 counting only the distinct ones).

The product of its (nonzero) digits is 13608, while the sum is 36.

The square root of 161667090 is about 12714.8373957357. The cubic root of 161667090 is about 544.7625034839.

The spelling of 161667090 in words is "one hundred sixty-one million, six hundred sixty-seven thousand, ninety".