6506900021 has 2 divisors, whose sum is σ = 6506900022. Its totient is φ = 6506900020.

The previous prime is 6506899981. The next prime is 6506900107. The reversal of 6506900021 is 1200096056.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6117429796 + 389470225 = 78214^2 + 19735^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6506900021 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6506900221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3253450010 + 3253450011.

It is an arithmetic number, because the mean of its divisors is an integer number (3253450011).

Almost surely, 2^6506900021 is an apocalyptic number.

It is an amenable number.

6506900021 is a deficient number, since it is larger than the sum of its proper divisors (1).

6506900021 is an equidigital number, since it uses as much as digits as its factorization.

6506900021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 6506900021 is about 80665.3582462757. The cubic root of 6506900021 is about 1866.9157142448.

Adding to 6506900021 its reverse (1200096056), we get a palindrome (7706996077).

The spelling of 6506900021 in words is "six billion, five hundred six million, nine hundred thousand, twenty-one".