164545781 has 8 divisors (see below), whose sum is σ = 166849560. Its totient is φ = 162252288.

The previous prime is 164545753. The next prime is 164545789. The reversal of 164545781 is 187545461.

It can be written as a sum of positive squares in 4 ways, for example, as 1575025 + 162970756 = 1255^2 + 12766^2 .

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 164545781 - 2¹⁴ = 164529397 is a prime.

It is a super-2 number, since 2×164545781² = 54150628089799922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164545789) 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, 33005 + ... + 37661.

It is an arithmetic number, because the mean of its divisors is an integer number (20856195).

Almost surely, 2^164545781 is an apocalyptic number.

It is an amenable number.

164545781 is a deficient number, since it is larger than the sum of its proper divisors (2303779).

164545781 is an equidigital number, since it uses as much as digits as its factorization.

164545781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5143.

The product of its digits is 134400, while the sum is 41.

The square root of 164545781 is about 12827.5399434186. The cubic root of 164545781 is about 547.9768991008.

The spelling of 164545781 in words is "one hundred sixty-four million, five hundred forty-five thousand, seven hundred eighty-one".