221115161 has 4 divisors (see below), whose sum is σ = 222273024. Its totient is φ = 219957300.

The previous prime is 221115151. The next prime is 221115241. The reversal of 221115161 is 161511122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221115161 - 2²⁶ = 154006297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221115131) 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, 578645 + ... + 579026.

It is an arithmetic number, because the mean of its divisors is an integer number (55568256).

Almost surely, 2^221115161 is an apocalyptic number.

It is an amenable number.

221115161 is a deficient number, since it is larger than the sum of its proper divisors (1157863).

221115161 is a wasteful number, since it uses less digits than its factorization.

221115161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1157862.

The product of its digits is 120, while the sum is 20.

The square root of 221115161 is about 14869.9415264486. The cubic root of 221115161 is about 604.6993574908.

Adding to 221115161 its reverse (161511122), we get a palindrome (382626283).

It can be divided in two parts, 22111 and 5161, that added together give a palindrome (27272).

The spelling of 221115161 in words is "two hundred twenty-one million, one hundred fifteen thousand, one hundred sixty-one".