826661681 has 2 divisors, whose sum is σ = 826661682. Its totient is φ = 826661680.

The previous prime is 826661603. The next prime is 826661683. The reversal of 826661681 is 186166628.

826661681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 726841600 + 99820081 = 26960^2 + 9991^2 .

It is a cyclic number.

It is not a de Polignac number, because 826661681 - 2¹⁰ = 826660657 is a prime.

It is a super-2 number, since 2×826661681² = 1366739069667491522, which contains 22 as substring.

Together with 826661683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (826661683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 413330840 + 413330841.

It is an arithmetic number, because the mean of its divisors is an integer number (413330841).

Almost surely, 2^826661681 is an apocalyptic number.

It is an amenable number.

826661681 is a deficient number, since it is larger than the sum of its proper divisors (1).

826661681 is an equidigital number, since it uses as much as digits as its factorization.

826661681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 44.

The square root of 826661681 is about 28751.7248352164. The cubic root of 826661681 is about 938.5179910013.

The spelling of 826661681 in words is "eight hundred twenty-six million, six hundred sixty-one thousand, six hundred eighty-one".