99820081 has 9 divisors (see below), whose sum is σ = 101848491. Its totient is φ = 97831872.

The previous prime is 99820051. The next prime is 99820087. The reversal of 99820081 is 18002899.

The square root of 99820081 is 9991.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 44823025 + 54997056 = 6695^2 + 7416^2 .

It is not a de Polignac number, because 99820081 - 2⁹ = 99819569 is a prime.

It is a super-2 number, since 2×99820081² = 19928097141693122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99820081.

It is not an unprimeable number, because it can be changed into a prime (99820087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 969076 + ... + 969178.

It is an arithmetic number, because the mean of its divisors is an integer number (11316499).

Almost surely, 2^99820081 is an apocalyptic number.

99820081 is the 9991-st square number.

99820081 is the 4996-th centered octagonal number.

It is an amenable number.

99820081 is a deficient number, since it is larger than the sum of its proper divisors (2028410).

99820081 is an frugal number, since it uses more digits than its factorization.

99820081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 200 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 37.

The cubic root of 99820081 is about 463.8803462402.

The spelling of 99820081 in words is "ninety-nine million, eight hundred twenty thousand, eighty-one".