840268362721 has 2 divisors, whose sum is σ = 840268362722. Its totient is φ = 840268362720.

The previous prime is 840268362719. The next prime is 840268362727. The reversal of 840268362721 is 127263862048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 489490532496 + 350777830225 = 699636^2 + 592265^2 .

It is a cyclic number.

It is not a de Polignac number, because 840268362721 - 2¹ = 840268362719 is a prime.

Together with 840268362719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (840268362727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420134181360 + 420134181361.

It is an arithmetic number, because the mean of its divisors is an integer number (420134181361).

Almost surely, 2^840268362721 is an apocalyptic number.

It is an amenable number.

840268362721 is a deficient number, since it is larger than the sum of its proper divisors (1).

840268362721 is an equidigital number, since it uses as much as digits as its factorization.

840268362721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1548288, while the sum is 49.

The spelling of 840268362721 in words is "eight hundred forty billion, two hundred sixty-eight million, three hundred sixty-two thousand, seven hundred twenty-one".