161691270 has 64 divisors (see below), whose sum is σ = 425053440. Its totient is φ = 39120768.

The previous prime is 161691251. The next prime is 161691307. The reversal of 161691270 is 72196161.

It is a super-3 number, since 3×161691270³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19497 + ... + 26523.

It is an arithmetic number, because the mean of its divisors is an integer number (6641460).

Almost surely, 2^161691270 is an apocalyptic number.

161691270 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 161691270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212526720).

161691270 is an abundant number, since it is smaller than the sum of its proper divisors (263362170).

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

161691270 is a wasteful number, since it uses less digits than its factorization.

161691270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7109.

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 161691270 is about 12715.7882178023. The cubic root of 161691270 is about 544.7896615585.

The spelling of 161691270 in words is "one hundred sixty-one million, six hundred ninety-one thousand, two hundred seventy".