999874991 has 2 divisors, whose sum is σ = 999874992. Its totient is φ = 999874990.

The previous prime is 999874987. The next prime is 999875003. The reversal of 999874991 is 199478999.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 999874991 - 2² = 999874987 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999874901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499937495 + 499937496.

It is an arithmetic number, because the mean of its divisors is an integer number (499937496).

Almost surely, 2^999874991 is an apocalyptic number.

999874991 is a deficient number, since it is larger than the sum of its proper divisors (1).

999874991 is an equidigital number, since it uses as much as digits as its factorization.

999874991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13226976, while the sum is 65.

The square root of 999874991 is about 31620.7999740677. The cubic root of 999874991 is about 999.9583285969.

The spelling of 999874991 in words is "nine hundred ninety-nine million, eight hundred seventy-four thousand, nine hundred ninety-one".