999921977 has 2 divisors, whose sum is σ = 999921978. Its totient is φ = 999921976.

The previous prime is 999921947. The next prime is 999921983. The reversal of 999921977 is 779129999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 927263401 + 72658576 = 30451^2 + 8524^2 .

It is a cyclic number.

It is not a de Polignac number, because 999921977 - 2¹⁰ = 999920953 is a prime.

It is not a weakly prime, because it can be changed into another prime (999921907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499960988 + 499960989.

It is an arithmetic number, because the mean of its divisors is an integer number (499960989).

Almost surely, 2^999921977 is an apocalyptic number.

It is an amenable number.

999921977 is a deficient number, since it is larger than the sum of its proper divisors (1).

999921977 is an equidigital number, since it uses as much as digits as its factorization.

999921977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5786802, while the sum is 62.

The square root of 999921977 is about 31621.5429256702. The cubic root of 999921977 is about 999.9739916569.

The spelling of 999921977 in words is "nine hundred ninety-nine million, nine hundred twenty-one thousand, nine hundred seventy-seven".