6451212821 has 2 divisors, whose sum is σ = 6451212822. Its totient is φ = 6451212820.

The previous prime is 6451212787. The next prime is 6451212913. The reversal of 6451212821 is 1282121546.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6450338596 + 874225 = 80314^2 + 935^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6451212821 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 (6451211821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3225606410 + 3225606411.

It is an arithmetic number, because the mean of its divisors is an integer number (3225606411).

Almost surely, 2^6451212821 is an apocalyptic number.

It is an amenable number.

6451212821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6451212821 is an equidigital number, since it uses as much as digits as its factorization.

6451212821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7680, while the sum is 32.

The square root of 6451212821 is about 80319.4423598670. The cubic root of 6451212821 is about 1861.5746503789.

The spelling of 6451212821 in words is "six billion, four hundred fifty-one million, two hundred twelve thousand, eight hundred twenty-one".