810101 has 4 divisors (see below), whose sum is σ = 857772. Its totient is φ = 762432.

The previous prime is 810091. The next prime is 810109. The reversal of 810101 is 101018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 448900 + 361201 = 670^2 + 601^2 .

It is a cyclic number.

It is not a de Polignac number, because 810101 - 2¹⁴ = 793717 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

810101 is a modest number, since divided by 101 gives 81 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23810 + ... + 23843.

It is an arithmetic number, because the mean of its divisors is an integer number (214443).

2⁸¹⁰¹⁰¹ is an apocalyptic number.

It is an amenable number.

810101 is a deficient number, since it is larger than the sum of its proper divisors (47671).

810101 is a wasteful number, since it uses less digits than its factorization.

810101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47670.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 810101 is about 900.0561093621. The cubic root of 810101 is about 93.2208494680.

Adding to 810101 its reverse (101018), we get a palindrome (911119).

It can be divided in two parts, 810 and 101, that multiplied together give a triangular number (81810 = T₄₀₄).

The spelling of 810101 in words is "eight hundred ten thousand, one hundred one".