1021000261 has 2 divisors, whose sum is σ = 1021000262. Its totient is φ = 1021000260.

The previous prime is 1021000259. The next prime is 1021000319. The reversal of 1021000261 is 1620001201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 553143361 + 467856900 = 23519^2 + 21630^2 .

It is a cyclic number.

It is not a de Polignac number, because 1021000261 - 2¹ = 1021000259 is a prime.

Together with 1021000259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021000231) 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, 510500130 + 510500131.

It is an arithmetic number, because the mean of its divisors is an integer number (510500131).

Almost surely, 2^1021000261 is an apocalyptic number.

It is an amenable number.

1021000261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021000261 is an equidigital number, since it uses as much as digits as its factorization.

1021000261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 1021000261 is about 31953.0947014526. The cubic root of 1021000261 is about 1006.9516495875.

Adding to 1021000261 its reverse (1620001201), we get a palindrome (2641001462).

The spelling of 1021000261 in words is "one billion, twenty-one million, two hundred sixty-one", and thus it is an aban number.