99581987 has 2 divisors, whose sum is σ = 99581988. Its totient is φ = 99581986.

The previous prime is 99581947. The next prime is 99582031. The reversal of 99581987 is 78918599.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99581987 - 2¹⁶ = 99516451 is a prime.

It is not a weakly prime, because it can be changed into another prime (99581947) 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 as a sum of consecutive naturals, namely, 49790993 + 49790994.

It is an arithmetic number, because the mean of its divisors is an integer number (49790994).

Almost surely, 2^99581987 is an apocalyptic number.

99581987 is a deficient number, since it is larger than the sum of its proper divisors (1).

99581987 is an equidigital number, since it uses as much as digits as its factorization.

99581987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1632960, while the sum is 56.

The square root of 99581987 is about 9979.0774623710. The cubic root of 99581987 is about 463.5112319412.

The spelling of 99581987 in words is "ninety-nine million, five hundred eighty-one thousand, nine hundred eighty-seven".