10821781 has 2 divisors, whose sum is σ = 10821782. Its totient is φ = 10821780.

The previous prime is 10821763. The next prime is 10821829. The reversal of 10821781 is 18712801.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10692900 + 128881 = 3270^2 + 359^2 .

It is a cyclic number.

It is not a de Polignac number, because 10821781 - 2¹⁵ = 10789013 is a prime.

It is a super-2 number, since 2×10821781² = 234221888023922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10821761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5410890 + 5410891.

It is an arithmetic number, because the mean of its divisors is an integer number (5410891).

Almost surely, 2^10821781 is an apocalyptic number.

It is an amenable number.

10821781 is a deficient number, since it is larger than the sum of its proper divisors (1).

10821781 is an equidigital number, since it uses as much as digits as its factorization.

10821781 is an odious number, because the sum of its binary digits is odd.

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

The square root of 10821781 is about 3289.6475495104. The cubic root of 10821781 is about 221.1903862287.

The spelling of 10821781 in words is "ten million, eight hundred twenty-one thousand, seven hundred eighty-one".