99999900212121 has 96 divisors (see below), whose sum is σ = 182692680654848. Its totient is φ = 51290601753600.

The previous prime is 99999900212071. The next prime is 99999900212129. The reversal of 99999900212121 is 12121200999999.

It is not a de Polignac number, because 99999900212121 - 2¹⁷ = 99999900081049 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (99999900212129) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 49216296 + ... + 51207846.

Almost surely, 2^{99999900212121} is an apocalyptic number.

99999900212121 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

It is an amenable number.

99999900212121 is a deficient number, since it is larger than the sum of its proper divisors (82692780442727).

99999900212121 is a wasteful number, since it uses less digits than its factorization.

99999900212121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1993271 (or 1993268 counting only the distinct ones).

The product of its (nonzero) digits is 4251528, while the sum is 63.

The spelling of 99999900212121 in words is "ninety-nine trillion, nine hundred ninety-nine billion, nine hundred million, two hundred twelve thousand, one hundred twenty-one".