161051221 has 4 divisors (see below), whose sum is σ = 168053472. Its totient is φ = 154048972.

The previous prime is 161051207. The next prime is 161051249. The reversal of 161051221 is 122150161.

161051221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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: 122150161 = 7 ⋅17450023.

It is a cyclic number.

It is not a de Polignac number, because 161051221 - 2⁹ = 161050709 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 (161001221) 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, 3501091 + ... + 3501136.

It is an arithmetic number, because the mean of its divisors is an integer number (42013368).

Almost surely, 2^161051221 is an apocalyptic number.

It is an amenable number.

161051221 is a deficient number, since it is larger than the sum of its proper divisors (7002251).

161051221 is an equidigital number, since it uses as much as digits as its factorization.

161051221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7002250.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 161051221 is about 12690.5957700968. The cubic root of 161051221 is about 544.0698676212.

The spelling of 161051221 in words is "one hundred sixty-one million, fifty-one thousand, two hundred twenty-one".