164721729 has 4 divisors (see below), whose sum is σ = 219628976. Its totient is φ = 109814484.

The previous prime is 164721727. The next prime is 164721757. The reversal of 164721729 is 927127461.

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 not a de Polignac number, because 164721729 - 2¹ = 164721727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (164721727) 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, 27453619 + ... + 27453624.

It is an arithmetic number, because the mean of its divisors is an integer number (54907244).

Almost surely, 2^164721729 is an apocalyptic number.

It is an amenable number.

164721729 is a deficient number, since it is larger than the sum of its proper divisors (54907247).

164721729 is an equidigital number, since it uses as much as digits as its factorization.

164721729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54907246.

The product of its digits is 42336, while the sum is 39.

The square root of 164721729 is about 12834.3963239414. The cubic root of 164721729 is about 548.1721458658.

The spelling of 164721729 in words is "one hundred sixty-four million, seven hundred twenty-one thousand, seven hundred twenty-nine".