161372221 has 4 divisors (see below), whose sum is σ = 161476000. Its totient is φ = 161268444.

The previous prime is 161372213. The next prime is 161372231. The reversal of 161372221 is 122273161.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 122273161 = 3433 ⋅35617.

It is a cyclic number.

It is not a de Polignac number, because 161372221 - 2³ = 161372213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161372201) 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, 49521 + ... + 52678.

It is an arithmetic number, because the mean of its divisors is an integer number (40369000).

Almost surely, 2^161372221 is an apocalyptic number.

It is an amenable number.

161372221 is a deficient number, since it is larger than the sum of its proper divisors (103779).

161372221 is a wasteful number, since it uses less digits than its factorization.

161372221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103778.

The product of its digits is 1008, while the sum is 25.

The square root of 161372221 is about 12703.2366348108. The cubic root of 161372221 is about 544.4310995372.

The spelling of 161372221 in words is "one hundred sixty-one million, three hundred seventy-two thousand, two hundred twenty-one".