999121787 has 2 divisors, whose sum is σ = 999121788. Its totient is φ = 999121786.

The previous prime is 999121763. The next prime is 999121789. The reversal of 999121787 is 787121999.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999121787 is a prime.

Together with 999121789, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (999121789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499560893 + 499560894.

It is an arithmetic number, because the mean of its divisors is an integer number (499560894).

Almost surely, 2^999121787 is an apocalyptic number.

999121787 is a deficient number, since it is larger than the sum of its proper divisors (1).

999121787 is an equidigital number, since it uses as much as digits as its factorization.

999121787 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 571536, while the sum is 53.

The square root of 999121787 is about 31608.8877849253. The cubic root of 999121787 is about 999.7071765962.

The spelling of 999121787 in words is "nine hundred ninety-nine million, one hundred twenty-one thousand, seven hundred eighty-seven".