6991904473 has 2 divisors, whose sum is σ = 6991904474. Its totient is φ = 6991904472.

The previous prime is 6991904419. The next prime is 6991904503. The reversal of 6991904473 is 3744091996.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6423701904 + 568202569 = 80148^2 + 23837^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6991904473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6991904473.

It is not a weakly prime, because it can be changed into another prime (6991904173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3495952236 + 3495952237.

It is an arithmetic number, because the mean of its divisors is an integer number (3495952237).

Almost surely, 2^6991904473 is an apocalyptic number.

It is an amenable number.

6991904473 is a deficient number, since it is larger than the sum of its proper divisors (1).

6991904473 is an equidigital number, since it uses as much as digits as its factorization.

6991904473 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 52.

The square root of 6991904473 is about 83617.6086300009. The cubic root of 6991904473 is about 1912.1934608761.

The spelling of 6991904473 in words is "six billion, nine hundred ninety-one million, nine hundred four thousand, four hundred seventy-three".