999621971 has 2 divisors, whose sum is σ = 999621972. Its totient is φ = 999621970.

The previous prime is 999621937. The next prime is 999622009. The reversal of 999621971 is 179126999.

999621971 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999621971 - 2⁶ = 999621907 is a prime.

It is not a weakly prime, because it can be changed into another prime (999621911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499810985 + 499810986.

It is an arithmetic number, because the mean of its divisors is an integer number (499810986).

Almost surely, 2^999621971 is an apocalyptic number.

999621971 is a deficient number, since it is larger than the sum of its proper divisors (1).

999621971 is an equidigital number, since it uses as much as digits as its factorization.

999621971 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 551124, while the sum is 53.

The square root of 999621971 is about 31616.7988733838. The cubic root of 999621971 is about 999.8739744516.

The spelling of 999621971 in words is "nine hundred ninety-nine million, six hundred twenty-one thousand, nine hundred seventy-one".