99555821 has 2 divisors, whose sum is σ = 99555822. Its totient is φ = 99555820.

The previous prime is 99555817. The next prime is 99555851. The reversal of 99555821 is 12855599.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76650025 + 22905796 = 8755^2 + 4786^2 .

It is a cyclic number.

It is not a de Polignac number, because 99555821 - 2² = 99555817 is a prime.

It is a super-2 number, since 2×99555821² = 19822722989968082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99555851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49777910 + 49777911.

It is an arithmetic number, because the mean of its divisors is an integer number (49777911).

Almost surely, 2^99555821 is an apocalyptic number.

It is an amenable number.

99555821 is a deficient number, since it is larger than the sum of its proper divisors (1).

99555821 is an equidigital number, since it uses as much as digits as its factorization.

99555821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 162000, while the sum is 44.

The square root of 99555821 is about 9977.7663332030. The cubic root of 99555821 is about 463.4706312339.

The spelling of 99555821 in words is "ninety-nine million, five hundred fifty-five thousand, eight hundred twenty-one".