99988591 has 2 divisors, whose sum is σ = 99988592. Its totient is φ = 99988590.

The previous prime is 99988579. The next prime is 99988597. The reversal of 99988591 is 19588999.

99988591 = T₈₁₆₃ + T₈₁₆₄ + T₈₁₆₅.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (19588999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99988591 - 2¹³ = 99980399 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99988597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49994295 + 49994296.

It is an arithmetic number, because the mean of its divisors is an integer number (49994296).

Almost surely, 2^99988591 is an apocalyptic number.

99988591 is the 8165-th centered triangular number.

99988591 is a deficient number, since it is larger than the sum of its proper divisors (1).

99988591 is an equidigital number, since it uses as much as digits as its factorization.

99988591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2099520, while the sum is 58.

The square root of 99988591 is about 9999.4295337284. The cubic root of 99988591 is about 464.1412307276.

The spelling of 99988591 in words is "ninety-nine million, nine hundred eighty-eight thousand, five hundred ninety-one".