821135057 has 2 divisors, whose sum is σ = 821135058. Its totient is φ = 821135056.

The previous prime is 821135053. The next prime is 821135059. The reversal of 821135057 is 750531128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532271041 + 288864016 = 23071^2 + 16996^2 .

It is a cyclic number.

It is not a de Polignac number, because 821135057 - 2² = 821135053 is a prime.

Together with 821135059, 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 (821135053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410567528 + 410567529.

It is an arithmetic number, because the mean of its divisors is an integer number (410567529).

Almost surely, 2^821135057 is an apocalyptic number.

It is an amenable number.

821135057 is a deficient number, since it is larger than the sum of its proper divisors (1).

821135057 is an equidigital number, since it uses as much as digits as its factorization.

821135057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8400, while the sum is 32.

The square root of 821135057 is about 28655.4542277731. The cubic root of 821135057 is about 936.4218340069.

The spelling of 821135057 in words is "eight hundred twenty-one million, one hundred thirty-five thousand, fifty-seven".