999258721 has 2 divisors, whose sum is σ = 999258722. Its totient is φ = 999258720.

The previous prime is 999258677. The next prime is 999258727. The reversal of 999258721 is 127852999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 975687696 + 23571025 = 31236^2 + 4855^2 .

It is a cyclic number.

It is not a de Polignac number, because 999258721 - 2¹¹ = 999256673 is a prime.

It is a super-3 number, since 3×999258721³ (a number of 28 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (999258727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499629360 + 499629361.

It is an arithmetic number, because the mean of its divisors is an integer number (499629361).

Almost surely, 2^999258721 is an apocalyptic number.

It is an amenable number.

999258721 is a deficient number, since it is larger than the sum of its proper divisors (1).

999258721 is an equidigital number, since it uses as much as digits as its factorization.

999258721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 816480, while the sum is 52.

The square root of 999258721 is about 31611.0537787022. The cubic root of 999258721 is about 999.7528459199.

The spelling of 999258721 in words is "nine hundred ninety-nine million, two hundred fifty-eight thousand, seven hundred twenty-one".