99855421 has 2 divisors, whose sum is σ = 99855422. Its totient is φ = 99855420.

The previous prime is 99855409. The next prime is 99855449. The reversal of 99855421 is 12455899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 87703225 + 12152196 = 9365^2 + 3486^2 .

It is an emirp because it is prime and its reverse (12455899) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99855421 is a prime.

It is a super-2 number, since 2×99855421² = 19942210206174482, which contains 22 as substring.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99855461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49927710 + 49927711.

It is an arithmetic number, because the mean of its divisors is an integer number (49927711).

Almost surely, 2^99855421 is an apocalyptic number.

It is an amenable number.

99855421 is a deficient number, since it is larger than the sum of its proper divisors (1).

99855421 is an equidigital number, since it uses as much as digits as its factorization.

99855421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 129600, while the sum is 43.

The square root of 99855421 is about 9992.7684352235. The cubic root of 99855421 is about 463.9350833800.

The spelling of 99855421 in words is "ninety-nine million, eight hundred fifty-five thousand, four hundred twenty-one".