6698599021 has 2 divisors, whose sum is σ = 6698599022. Its totient is φ = 6698599020.

The previous prime is 6698598997. The next prime is 6698599049. The reversal of 6698599021 is 1209958966.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6562620100 + 135978921 = 81010^2 + 11661^2 .

It is a cyclic number.

It is not a de Polignac number, because 6698599021 - 2⁹ = 6698598509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6698599091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3349299510 + 3349299511.

It is an arithmetic number, because the mean of its divisors is an integer number (3349299511).

Almost surely, 2^6698599021 is an apocalyptic number.

It is an amenable number.

6698599021 is a deficient number, since it is larger than the sum of its proper divisors (1).

6698599021 is an equidigital number, since it uses as much as digits as its factorization.

6698599021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2099520, while the sum is 55.

The square root of 6698599021 is about 81844.9694300145. The cubic root of 6698599021 is about 1885.0722223241.

The spelling of 6698599021 in words is "six billion, six hundred ninety-eight million, five hundred ninety-nine thousand, twenty-one".