164327721 has 4 divisors (see below), whose sum is σ = 219103632. Its totient is φ = 109551812.

The previous prime is 164327699. The next prime is 164327741. The reversal of 164327721 is 127723461.

164327721 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: 127723461 = 3 ⋅42574487.

It is a cyclic number.

It is not a de Polignac number, because 164327721 - 2¹⁴ = 164311337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (164327741) 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, 27387951 + ... + 27387956.

It is an arithmetic number, because the mean of its divisors is an integer number (54775908).

Almost surely, 2^164327721 is an apocalyptic number.

It is an amenable number.

164327721 is a deficient number, since it is larger than the sum of its proper divisors (54775911).

164327721 is an equidigital number, since it uses as much as digits as its factorization.

164327721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54775910.

The product of its digits is 14112, while the sum is 33.

The square root of 164327721 is about 12819.0374443638. The cubic root of 164327721 is about 547.7347280663.

The spelling of 164327721 in words is "one hundred sixty-four million, three hundred twenty-seven thousand, seven hundred twenty-one".