999901109 has 2 divisors, whose sum is σ = 999901110. Its totient is φ = 999901108.

The previous prime is 999901069. The next prime is 999901117. The reversal of 999901109 is 901109999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 573602500 + 426298609 = 23950^2 + 20647^2 .

It is an emirp because it is prime and its reverse (901109999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999901109 - 2²⁴ = 983123893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999901139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499950554 + 499950555.

It is an arithmetic number, because the mean of its divisors is an integer number (499950555).

Almost surely, 2^999901109 is an apocalyptic number.

It is an amenable number.

999901109 is a deficient number, since it is larger than the sum of its proper divisors (1).

999901109 is an equidigital number, since it uses as much as digits as its factorization.

999901109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 59049, while the sum is 47.

The square root of 999901109 is about 31621.2129590248. The cubic root of 999901109 is about 999.9670352467.

The spelling of 999901109 in words is "nine hundred ninety-nine million, nine hundred one thousand, one hundred nine".