999637988 has 12 divisors (see below), whose sum is σ = 1778045052. Its totient is φ = 491625120.

The previous prime is 999637987. The next prime is 999637993. The reversal of 999637988 is 889736999.

It can be written as a sum of positive squares in 2 ways, for example, as 127735204 + 871902784 = 11302^2 + 29528^2 .

It is a super-2 number, since 2×999637988² = 1998552214105376288, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (999637987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2048195 + ... + 2048682.

It is an arithmetic number, because the mean of its divisors is an integer number (148170421).

Almost surely, 2^999637988 is an apocalyptic number.

It is an amenable number.

999637988 is a deficient number, since it is larger than the sum of its proper divisors (778407064).

999637988 is a wasteful number, since it uses less digits than its factorization.

999637988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4096942 (or 4096940 counting only the distinct ones).

The product of its digits is 52907904, while the sum is 68.

The square root of 999637988 is about 31617.0521712572. The cubic root of 999637988 is about 999.8793147690.

The spelling of 999637988 in words is "nine hundred ninety-nine million, six hundred thirty-seven thousand, nine hundred eighty-eight".