999921947 has 2 divisors, whose sum is σ = 999921948. Its totient is φ = 999921946.

The previous prime is 999921931. The next prime is 999921977. The reversal of 999921947 is 749129999.

999921947 is an esthetic number in base 4, because in such base its adjacent digits differ by 1.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999921947 - 2⁴ = 999921931 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, 499960973 + 499960974.

It is an arithmetic number, because the mean of its divisors is an integer number (499960974).

Almost surely, 2^999921947 is an apocalyptic number.

999921947 is a deficient number, since it is larger than the sum of its proper divisors (1).

999921947 is an equidigital number, since it uses as much as digits as its factorization.

999921947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3306744, while the sum is 59.

The square root of 999921947 is about 31621.5424513100. The cubic root of 999921947 is about 999.9739816564.

The spelling of 999921947 in words is "nine hundred ninety-nine million, nine hundred twenty-one thousand, nine hundred forty-seven".