999961989 has 16 divisors (see below), whose sum is σ = 1466395392. Its totient is φ = 602267328.

The previous prime is 999961979. The next prime is 999962057. The reversal of 999961989 is 989169999.

It is not a de Polignac number, because 999961989 - 2⁸ = 999961733 is a prime.

It is a super-2 number, since 2×999961989² = 1999847958889672242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999961939) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 270934 + ... + 274599.

It is an arithmetic number, because the mean of its divisors is an integer number (91649712).

Almost surely, 2^999961989 is an apocalyptic number.

It is an amenable number.

999961989 is a deficient number, since it is larger than the sum of its proper divisors (466433403).

999961989 is a wasteful number, since it uses less digits than its factorization.

999961989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545596.

The product of its digits is 25509168, while the sum is 69.

The square root of 999961989 is about 31622.1755892918. The cubic root of 999961989 is about 999.9873295061.

The spelling of 999961989 in words is "nine hundred ninety-nine million, nine hundred sixty-one thousand, nine hundred eighty-nine".