161011511 has 4 divisors (see below), whose sum is σ = 161037552. Its totient is φ = 160985472.

The previous prime is 161011481. The next prime is 161011577. The reversal of 161011511 is 115110161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161011511 - 2⁶ = 161011447 is a prime.

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 161011511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161011211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2135 + ... + 18071.

It is an arithmetic number, because the mean of its divisors is an integer number (40259388).

Almost surely, 2^161011511 is an apocalyptic number.

161011511 is a deficient number, since it is larger than the sum of its proper divisors (26041).

161011511 is a wasteful number, since it uses less digits than its factorization.

161011511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26040.

The product of its (nonzero) digits is 30, while the sum is 17.

The square root of 161011511 is about 12689.0311292864. The cubic root of 161011511 is about 544.0251472930.

Adding to 161011511 its reverse (115110161), we get a palindrome (276121672).

The spelling of 161011511 in words is "one hundred sixty-one million, eleven thousand, five hundred eleven".