99912581 has 2 divisors, whose sum is σ = 99912582. Its totient is φ = 99912580.

The previous prime is 99912577. The next prime is 99912629. The reversal of 99912581 is 18521999.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 74822500 + 25090081 = 8650^2 + 5009^2 .

It is an emirp because it is prime and its reverse (18521999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99912581 - 2² = 99912577 is a prime.

It is a super-2 number, since 2×99912581² = 19965047684163122, 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 (99912541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49956290 + 49956291.

It is an arithmetic number, because the mean of its divisors is an integer number (49956291).

Almost surely, 2^99912581 is an apocalyptic number.

It is an amenable number.

99912581 is a deficient number, since it is larger than the sum of its proper divisors (1).

99912581 is an equidigital number, since it uses as much as digits as its factorization.

99912581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 44.

The square root of 99912581 is about 9995.6280943220. The cubic root of 99912581 is about 464.0235895780.

The spelling of 99912581 in words is "ninety-nine million, nine hundred twelve thousand, five hundred eighty-one".