1299521261 has 2 divisors, whose sum is σ = 1299521262. Its totient is φ = 1299521260.

The previous prime is 1299521239. The next prime is 1299521263. The reversal of 1299521261 is 1621259921.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 907877161 + 391644100 = 30131^2 + 19790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1299521261 is a prime.

Together with 1299521263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1299521263) 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, 649760630 + 649760631.

It is an arithmetic number, because the mean of its divisors is an integer number (649760631).

Almost surely, 2^1299521261 is an apocalyptic number.

It is an amenable number.

1299521261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1299521261 is an equidigital number, since it uses as much as digits as its factorization.

1299521261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19440, while the sum is 38.

The square root of 1299521261 is about 36048.8732278833. The cubic root of 1299521261 is about 1091.2588942179.

The spelling of 1299521261 in words is "one billion, two hundred ninety-nine million, five hundred twenty-one thousand, two hundred sixty-one".