999995100721 has 2 divisors, whose sum is σ = 999995100722. Its totient is φ = 999995100720.

The previous prime is 999995100719. The next prime is 999995100773. The reversal of 999995100721 is 127001599999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 866211797025 + 133783303696 = 930705^2 + 365764^2 .

It is a cyclic number.

It is not a de Polignac number, because 999995100721 - 2¹ = 999995100719 is a prime.

Together with 999995100719, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 999995100721.

It is not a weakly prime, because it can be changed into another prime (999995100781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499997550360 + 499997550361.

It is an arithmetic number, because the mean of its divisors is an integer number (499997550361).

Almost surely, 2^999995100721 is an apocalyptic number.

It is an amenable number.

999995100721 is a deficient number, since it is larger than the sum of its proper divisors (1).

999995100721 is an equidigital number, since it uses as much as digits as its factorization.

999995100721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4133430, while the sum is 61.

The spelling of 999995100721 in words is "nine hundred ninety-nine billion, nine hundred ninety-five million, one hundred thousand, seven hundred twenty-one".