821897 has 2 divisors, whose sum is σ = 821898. Its totient is φ = 821896.

The previous prime is 821879. The next prime is 821911. The reversal of 821897 is 798128.

It is a happy number.

Together with previous prime (821879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 712336 + 109561 = 844^2 + 331^2 .

It is a cyclic number.

It is not a de Polignac number, because 821897 - 2⁶ = 821833 is a prime.

It is an Ulam number.

It is not a weakly prime, because it can be changed into another prime (821827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410948 + 410949.

It is an arithmetic number, because the mean of its divisors is an integer number (410949).

2⁸²¹⁸⁹⁷ is an apocalyptic number.

It is an amenable number.

821897 is a deficient number, since it is larger than the sum of its proper divisors (1).

821897 is an equidigital number, since it uses as much as digits as its factorization.

821897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 821897 is about 906.5853517458. The cubic root of 821897 is about 93.6711384218.

The spelling of 821897 in words is "eight hundred twenty-one thousand, eight hundred ninety-seven".