999001901 has 2 divisors, whose sum is σ = 999001902. Its totient is φ = 999001900.

The previous prime is 999001897. The next prime is 999001903. The reversal of 999001901 is 109100999.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 600201001 + 398800900 = 24499^2 + 19970^2 .

It is a cyclic number.

It is not a de Polignac number, because 999001901 - 2² = 999001897 is a prime.

It is a super-2 number, since 2×999001901² = 1996009596403227602, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 999001903, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999001903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499500950 + 499500951.

It is an arithmetic number, because the mean of its divisors is an integer number (499500951).

Almost surely, 2^999001901 is an apocalyptic number.

It is an amenable number.

999001901 is a deficient number, since it is larger than the sum of its proper divisors (1).

999001901 is an equidigital number, since it uses as much as digits as its factorization.

999001901 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6561, while the sum is 38.

The square root of 999001901 is about 31606.9913310331. The cubic root of 999001901 is about 999.6671895828.

The spelling of 999001901 in words is "nine hundred ninety-nine million, one thousand, nine hundred one".