999995100821 has 2 divisors, whose sum is σ = 999995100822. Its totient is φ = 999995100820.

The previous prime is 999995100781. The next prime is 999995100827. The reversal of 999995100821 is 128001599999.

999995100821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 680047622500 + 319947478321 = 824650^2 + 565639^2 .

It is a cyclic number.

It is not a de Polignac number, because 999995100821 - 2¹⁰ = 999995099797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999995100827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499997550410 + 499997550411.

It is an arithmetic number, because the mean of its divisors is an integer number (499997550411).

Almost surely, 2^999995100821 is an apocalyptic number.

It is an amenable number.

999995100821 is a deficient number, since it is larger than the sum of its proper divisors (1).

999995100821 is an equidigital number, since it uses as much as digits as its factorization.

999995100821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4723920, while the sum is 62.

The spelling of 999995100821 in words is "nine hundred ninety-nine billion, nine hundred ninety-five million, one hundred thousand, eight hundred twenty-one".