161067721 has 8 divisors (see below), whose sum is σ = 165247488. Its totient is φ = 156900000.

The previous prime is 161067701. The next prime is 161067727. The reversal of 161067721 is 127760161.

161067721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161067721 - 2⁹ = 161067209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161067727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28176 + ... + 33406.

It is an arithmetic number, because the mean of its divisors is an integer number (20655936).

Almost surely, 2^161067721 is an apocalyptic number.

It is an amenable number.

161067721 is a deficient number, since it is larger than the sum of its proper divisors (4179767).

161067721 is an equidigital number, since it uses as much as digits as its factorization.

161067721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6023.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 161067721 is about 12691.2458411300. The cubic root of 161067721 is about 544.0884473133.

The spelling of 161067721 in words is "one hundred sixty-one million, sixty-seven thousand, seven hundred twenty-one".