161661355 has 16 divisors (see below), whose sum is σ = 196236864. Its totient is φ = 127843200.

The previous prime is 161661349. The next prime is 161661359. The reversal of 161661355 is 553166161.

It is not a de Polignac number, because 161661355 - 2⁵ = 161661323 is a prime.

It is a super-2 number, since 2×161661355² = 52268787400872050, 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 161661355.

It is not an unprimeable number, because it can be changed into a prime (161661359) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 208749 + ... + 209521.

It is an arithmetic number, because the mean of its divisors is an integer number (12264804).

Almost surely, 2^161661355 is an apocalyptic number.

161661355 is a deficient number, since it is larger than the sum of its proper divisors (34575509).

161661355 is a wasteful number, since it uses less digits than its factorization.

161661355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1206.

The product of its digits is 16200, while the sum is 34.

The square root of 161661355 is about 12714.6118698134. The cubic root of 161661355 is about 544.7560617484.

The spelling of 161661355 in words is "one hundred sixty-one million, six hundred sixty-one thousand, three hundred fifty-five".