821535601 has 2 divisors, whose sum is σ = 821535602. Its totient is φ = 821535600.

The previous prime is 821535599. The next prime is 821535667. The reversal of 821535601 is 106535128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641304976 + 180230625 = 25324^2 + 13425^2 .

It is a cyclic number.

It is not a de Polignac number, because 821535601 - 2¹ = 821535599 is a prime.

Together with 821535599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (821535301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410767800 + 410767801.

It is an arithmetic number, because the mean of its divisors is an integer number (410767801).

Almost surely, 2^821535601 is an apocalyptic number.

It is an amenable number.

821535601 is a deficient number, since it is larger than the sum of its proper divisors (1).

821535601 is an equidigital number, since it uses as much as digits as its factorization.

821535601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 31.

The square root of 821535601 is about 28662.4423418522. The cubic root of 821535601 is about 936.5740692872.

The spelling of 821535601 in words is "eight hundred twenty-one million, five hundred thirty-five thousand, six hundred one".