6821400709 has 2 divisors, whose sum is σ = 6821400710. Its totient is φ = 6821400708.

The previous prime is 6821400661. The next prime is 6821400727. The reversal of 6821400709 is 9070041286.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5829780609 + 991620100 = 76353^2 + 31490^2 .

It is a cyclic number.

It is not a de Polignac number, because 6821400709 - 2¹⁹ = 6820876421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6821400749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3410700354 + 3410700355.

It is an arithmetic number, because the mean of its divisors is an integer number (3410700355).

Almost surely, 2^6821400709 is an apocalyptic number.

It is an amenable number.

6821400709 is a deficient number, since it is larger than the sum of its proper divisors (1).

6821400709 is an equidigital number, since it uses as much as digits as its factorization.

6821400709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 6821400709 is about 82591.7714363846. The cubic root of 6821400709 is about 1896.5218647975.

The spelling of 6821400709 in words is "six billion, eight hundred twenty-one million, four hundred thousand, seven hundred nine".