161511215 has 4 divisors (see below), whose sum is σ = 193813464. Its totient is φ = 129208968.

The previous prime is 161511199. The next prime is 161511227. The reversal of 161511215 is 512115161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161511215 - 2⁴ = 161511199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16151117 + ... + 16151126.

It is an arithmetic number, because the mean of its divisors is an integer number (48453366).

Almost surely, 2^161511215 is an apocalyptic number.

161511215 is a deficient number, since it is larger than the sum of its proper divisors (32302249).

161511215 is an equidigital number, since it uses as much as digits as its factorization.

161511215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32302248.

The product of its digits is 300, while the sum is 23.

The square root of 161511215 is about 12708.7062677520. The cubic root of 161511215 is about 544.5873654668.

Adding to 161511215 its reverse (512115161), we get a palindrome (673626376).

The spelling of 161511215 in words is "one hundred sixty-one million, five hundred eleven thousand, two hundred fifteen".