1021565849 has 2 divisors, whose sum is σ = 1021565850. Its totient is φ = 1021565848.

The previous prime is 1021565773. The next prime is 1021565851. The reversal of 1021565849 is 9485651201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 695113225 + 326452624 = 26365^2 + 18068^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021565849 - 2⁸ = 1021565593 is a prime.

Together with 1021565851, 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 (1021525849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510782924 + 510782925.

It is an arithmetic number, because the mean of its divisors is an integer number (510782925).

Almost surely, 2^1021565849 is an apocalyptic number.

It is an amenable number.

1021565849 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021565849 is an equidigital number, since it uses as much as digits as its factorization.

1021565849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 86400, while the sum is 41.

The square root of 1021565849 is about 31961.9437612921. The cubic root of 1021565849 is about 1007.1375504996.

The spelling of 1021565849 in words is "one billion, twenty-one million, five hundred sixty-five thousand, eight hundred forty-nine".