6991513 has 2 divisors, whose sum is σ = 6991514. Its totient is φ = 6991512.

The previous prime is 6991511. The next prime is 6991531. The reversal of 6991513 is 3151996.

Together with next prime (6991531) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5322249 + 1669264 = 2307^2 + 1292^2 .

It is a cyclic number.

It is not a de Polignac number, because 6991513 - 2¹ = 6991511 is a prime.

Together with 6991511, it forms a pair of twin primes.

6991513 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (6991511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495756 + 3495757.

It is an arithmetic number, because the mean of its divisors is an integer number (3495757).

Almost surely, 2^6991513 is an apocalyptic number.

It is an amenable number.

6991513 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991513 is an equidigital number, since it uses as much as digits as its factorization.

6991513 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7290, while the sum is 34.

The square root of 6991513 is about 2644.1469323772. The cubic root of 6991513 is about 191.2157772646.

The spelling of 6991513 in words is "six million, nine hundred ninety-one thousand, five hundred thirteen".