10218781 has 4 divisors (see below), whose sum is σ = 10386364. Its totient is φ = 10051200.

The previous prime is 10218763. The next prime is 10218829. The reversal of 10218781 is 18781201.

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 2044900 + 8173881 = 1430^2 + 2859^2 .

It is a cyclic number.

It is not a de Polignac number, because 10218781 - 2⁵ = 10218749 is a prime.

It is a super-2 number, since 2×10218781² = 208846970251922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10218731) 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, 83700 + ... + 83821.

It is an arithmetic number, because the mean of its divisors is an integer number (2596591).

Almost surely, 2^10218781 is an apocalyptic number.

It is an amenable number.

10218781 is a deficient number, since it is larger than the sum of its proper divisors (167583).

10218781 is an equidigital number, since it uses as much as digits as its factorization.

10218781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167582.

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 10218781 is about 3196.6828119161. The cubic root of 10218781 is about 217.0033128250.

Adding to 10218781 its reverse (18781201), we get a palindrome (28999982).

It can be divided in two parts, 10 and 218781, that added together give a triangular number (218791 = T₆₆₁).

The spelling of 10218781 in words is "ten million, two hundred eighteen thousand, seven hundred eighty-one".