1306506991 has 2 divisors, whose sum is σ = 1306506992. Its totient is φ = 1306506990.

The previous prime is 1306506979. The next prime is 1306507063. The reversal of 1306506991 is 1996056031.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1306506991 - 2⁵ = 1306506959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1306506911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 653253495 + 653253496.

It is an arithmetic number, because the mean of its divisors is an integer number (653253496).

Almost surely, 2^1306506991 is an apocalyptic number.

1306506991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1306506991 is an equidigital number, since it uses as much as digits as its factorization.

1306506991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43740, while the sum is 40.

The square root of 1306506991 is about 36145.6358499889. The cubic root of 1306506991 is about 1093.2107978399.

It can be divided in two parts, 130650 and 6991, that added together give a square (137641 = 371²).

The spelling of 1306506991 in words is "one billion, three hundred six million, five hundred six thousand, nine hundred ninety-one".