6403397621 has 2 divisors, whose sum is σ = 6403397622. Its totient is φ = 6403397620.

The previous prime is 6403397573. The next prime is 6403397647. The reversal of 6403397621 is 1267933046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6329952721 + 73444900 = 79561^2 + 8570^2 .

It is a cyclic number.

It is not a de Polignac number, because 6403397621 - 2⁶ = 6403397557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6403397681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3201698810 + 3201698811.

It is an arithmetic number, because the mean of its divisors is an integer number (3201698811).

Almost surely, 2^6403397621 is an apocalyptic number.

It is an amenable number.

6403397621 is a deficient number, since it is larger than the sum of its proper divisors (1).

6403397621 is an equidigital number, since it uses as much as digits as its factorization.

6403397621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 163296, while the sum is 41.

The square root of 6403397621 is about 80021.2323136803. The cubic root of 6403397621 is about 1856.9640244827.

The spelling of 6403397621 in words is "six billion, four hundred three million, three hundred ninety-seven thousand, six hundred twenty-one".