99812937665921 has 2 divisors, whose sum is σ = 99812937665922. Its totient is φ = 99812937665920.

The previous prime is 99812937665897. The next prime is 99812937665983. The reversal of 99812937665921 is 12956673921899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95629603763521 + 4183333902400 = 9779039^2 + 2045320^2 .

It is an emirp because it is prime and its reverse (12956673921899) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99812937665921 - 2³⁴ = 99795757796737 is a prime.

It is not a weakly prime, because it can be changed into another prime (99812937695921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49906468832960 + 49906468832961.

It is an arithmetic number, because the mean of its divisors is an integer number (49906468832961).

Almost surely, 2^{99812937665921} is an apocalyptic number.

It is an amenable number.

99812937665921 is a deficient number, since it is larger than the sum of its proper divisors (1).

99812937665921 is an equidigital number, since it uses as much as digits as its factorization.

99812937665921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 793618560, while the sum is 77.

The spelling of 99812937665921 in words is "ninety-nine trillion, eight hundred twelve billion, nine hundred thirty-seven million, six hundred sixty-five thousand, nine hundred twenty-one".