161660565 has 48 divisors (see below), whose sum is σ = 323683776. Its totient is φ = 73766400.

The previous prime is 161660561. The next prime is 161660573. The reversal of 161660565 is 565066161.

It is not a de Polignac number, because 161660565 - 2² = 161660561 is a prime.

It is a super-2 number, since 2×161660565² = 52268276552238450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161660561) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1191 + ... + 18020.

It is an arithmetic number, because the mean of its divisors is an integer number (6743412).

Almost surely, 2^161660565 is an apocalyptic number.

161660565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161660565 is an abundant number, since it is smaller than the sum of its proper divisors (162023211).

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

161660565 is a wasteful number, since it uses less digits than its factorization.

161660565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19250 (or 19247 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 161660565 is about 12714.5808031567. The cubic root of 161660565 is about 544.7551743831.

The spelling of 161660565 in words is "one hundred sixty-one million, six hundred sixty thousand, five hundred sixty-five".