161215109 has 4 divisors (see below), whose sum is σ = 175871040. Its totient is φ = 146559180.

The previous prime is 161215099. The next prime is 161215111. The reversal of 161215109 is 901512161.

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 161215109 - 2⁸ = 161214853 is a prime.

It is a super-2 number, since 2×161215109² = 51980622739763762, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161215139) 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, 7327949 + ... + 7327970.

It is an arithmetic number, because the mean of its divisors is an integer number (43967760).

Almost surely, 2^161215109 is an apocalyptic number.

It is an amenable number.

161215109 is a deficient number, since it is larger than the sum of its proper divisors (14655931).

161215109 is a wasteful number, since it uses less digits than its factorization.

161215109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14655930.

The product of its (nonzero) digits is 540, while the sum is 26.

The square root of 161215109 is about 12697.0511930920. The cubic root of 161215109 is about 544.2543561198.

The spelling of 161215109 in words is "one hundred sixty-one million, two hundred fifteen thousand, one hundred nine".