161009811 has 12 divisors (see below), whose sum is σ = 235184040. Its totient is φ = 106133280.

The previous prime is 161009809. The next prime is 161009831. The reversal of 161009811 is 118900161.

It is not a de Polignac number, because 161009811 - 2¹ = 161009809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161009801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 99705 + ... + 101306.

It is an arithmetic number, because the mean of its divisors is an integer number (19598670).

Almost surely, 2^161009811 is an apocalyptic number.

161009811 is a deficient number, since it is larger than the sum of its proper divisors (74174229).

161009811 is a wasteful number, since it uses less digits than its factorization.

161009811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201106 (or 201103 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 27.

The square root of 161009811 is about 12688.9641421197. The cubic root of 161009811 is about 544.0232326349.

Adding to 161009811 its reverse (118900161), we get a palindrome (279909972).

The spelling of 161009811 in words is "one hundred sixty-one million, nine thousand, eight hundred eleven".