6945686821 has 8 divisors (see below), whose sum is σ = 7355168280. Its totient is φ = 6536306688.

The previous prime is 6945686819. The next prime is 6945686831. The reversal of 6945686821 is 1286865496.

It can be written as a sum of positive squares in 4 ways, for example, as 1486102500 + 5459584321 = 38550^2 + 73889^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6945686821 - 2¹ = 6945686819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6945686801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 150885 + ... + 191461.

It is an arithmetic number, because the mean of its divisors is an integer number (919396035).

Almost surely, 2^6945686821 is an apocalyptic number.

It is an amenable number.

6945686821 is a deficient number, since it is larger than the sum of its proper divisors (409481459).

6945686821 is a wasteful number, since it uses less digits than its factorization.

6945686821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50663.

The product of its digits is 4976640, while the sum is 55.

The square root of 6945686821 is about 83340.7872593006. The cubic root of 6945686821 is about 1907.9708374291.

The spelling of 6945686821 in words is "six billion, nine hundred forty-five million, six hundred eighty-six thousand, eight hundred twenty-one".