99938996621 has 2 divisors, whose sum is σ = 99938996622. Its totient is φ = 99938996620.

The previous prime is 99938996617. The next prime is 99938996639. The reversal of 99938996621 is 12669983999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 95427859396 + 4511137225 = 308914^2 + 67165^2 .

It is a cyclic number.

It is not a de Polignac number, because 99938996621 - 2² = 99938996617 is a prime.

It is a super-2 number, since 2×99938996621² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99938996611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49969498310 + 49969498311.

It is an arithmetic number, because the mean of its divisors is an integer number (49969498311).

Almost surely, 2^99938996621 is an apocalyptic number.

It is an amenable number.

99938996621 is a deficient number, since it is larger than the sum of its proper divisors (1).

99938996621 is an equidigital number, since it uses as much as digits as its factorization.

99938996621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 102036672, while the sum is 71.

The spelling of 99938996621 in words is "ninety-nine billion, nine hundred thirty-eight million, nine hundred ninety-six thousand, six hundred twenty-one".