6991425909 has 24 divisors (see below), whose sum is σ = 11169492152. Its totient is φ = 4186131840.

The previous prime is 6991425887. The next prime is 6991425923. The reversal of 6991425909 is 9095241996.

6991425909 is a `hidden beast` number, since 6 + 9 + 9 + 1 + 42 + 590 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 192598884 + 6798827025 = 13878^2 + 82455^2 .

It is not a de Polignac number, because 6991425909 - 2⁷ = 6991425781 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6991425949) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 803182 + ... + 811839.

Almost surely, 2^6991425909 is an apocalyptic number.

It is an amenable number.

6991425909 is a deficient number, since it is larger than the sum of its proper divisors (4178066243).

6991425909 is a wasteful number, since it uses less digits than its factorization.

6991425909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1615077 (or 1615074 counting only the distinct ones).

The product of its (nonzero) digits is 1574640, while the sum is 54.

The square root of 6991425909 is about 83614.7469588948. The cubic root of 6991425909 is about 1912.1498329044.

The spelling of 6991425909 in words is "six billion, nine hundred ninety-one million, four hundred twenty-five thousand, nine hundred nine".