825661 has 2 divisors, whose sum is σ = 825662. Its totient is φ = 825660.

The previous prime is 825647. The next prime is 825679. The reversal of 825661 is 166528.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 783225 + 42436 = 885^2 + 206^2 .

It is a cyclic number.

It is not a de Polignac number, because 825661 - 2⁷ = 825533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (825611) 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 as a sum of consecutive naturals, namely, 412830 + 412831.

It is an arithmetic number, because the mean of its divisors is an integer number (412831).

2⁸²⁵⁶⁶¹ is an apocalyptic number.

It is an amenable number.

825661 is a deficient number, since it is larger than the sum of its proper divisors (1).

825661 is an equidigital number, since it uses as much as digits as its factorization.

825661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 28.

The square root of 825661 is about 908.6589018988. The cubic root of 825661 is about 93.8139143422.

The spelling of 825661 in words is "eight hundred twenty-five thousand, six hundred sixty-one".