161505643 has 16 divisors (see below), whose sum is σ = 183678880. Its totient is φ = 140776704.

The previous prime is 161505623. The next prime is 161505647. The reversal of 161505643 is 346505161.

It is a cyclic number.

It is not a de Polignac number, because 161505643 - 2¹³ = 161497451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161505647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91255 + ... + 93007.

It is an arithmetic number, because the mean of its divisors is an integer number (11479930).

Almost surely, 2^161505643 is an apocalyptic number.

161505643 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

161505643 is a deficient number, since it is larger than the sum of its proper divisors (22173237).

161505643 is a wasteful number, since it uses less digits than its factorization.

161505643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2158.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 161505643 is about 12708.4870460649. The cubic root of 161505643 is about 544.5811027939.

The spelling of 161505643 in words is "one hundred sixty-one million, five hundred five thousand, six hundred forty-three".