9999953243821 has 2 divisors, whose sum is σ = 9999953243822. Its totient is φ = 9999953243820.

The previous prime is 9999953243771. The next prime is 9999953243887. The reversal of 9999953243821 is 1283423599999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8303215140900 + 1696738102921 = 2881530^2 + 1302589^2 .

It is a cyclic number.

It is not a de Polignac number, because 9999953243821 - 2⁹ = 9999953243309 is a prime.

It is a super-2 number, since 2×9999953243821² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9999953243221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4999976621910 + 4999976621911.

It is an arithmetic number, because the mean of its divisors is an integer number (4999976621911).

Almost surely, 2^{9999953243821} is an apocalyptic number.

It is an amenable number.

9999953243821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999953243821 is an equidigital number, since it uses as much as digits as its factorization.

9999953243821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 340122240, while the sum is 73.

The spelling of 9999953243821 in words is "nine trillion, nine hundred ninety-nine billion, nine hundred fifty-three million, two hundred forty-three thousand, eight hundred twenty-one".