9979499396021 has 2 divisors, whose sum is σ = 9979499396022. Its totient is φ = 9979499396020.

The previous prime is 9979499396003. The next prime is 9979499396077. The reversal of 9979499396021 is 1206939949799.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9969774675025 + 9724720996 = 3157495^2 + 98614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9979499396021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9979499396221) 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, 4989749698010 + 4989749698011.

It is an arithmetic number, because the mean of its divisors is an integer number (4989749698011).

Almost surely, 2^{9979499396021} is an apocalyptic number.

It is an amenable number.

9979499396021 is a deficient number, since it is larger than the sum of its proper divisors (1).

9979499396021 is an equidigital number, since it uses as much as digits as its factorization.

9979499396021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 535692528, while the sum is 77.

The spelling of 9979499396021 in words is "nine trillion, nine hundred seventy-nine billion, four hundred ninety-nine million, three hundred ninety-six thousand, twenty-one".