999987280 has 40 divisors (see below), whose sum is σ = 2405147400. Its totient is φ = 386201088.

The previous prime is 999987227. The next prime is 999987281. The reversal of 999987280 is 82789999.

It can be written as a sum of positive squares in 4 ways, for example, as 63872064 + 936115216 = 7992^2 + 30596^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999987281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 213195 + ... + 217834.

It is an arithmetic number, because the mean of its divisors is an integer number (60128685).

Almost surely, 2^999987280 is an apocalyptic number.

It is an amenable number.

999987280 is an abundant number, since it is smaller than the sum of its proper divisors (1405160120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

999987280 is a wasteful number, since it uses less digits than its factorization.

999987280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431071 (or 431065 counting only the distinct ones).

The product of its (nonzero) digits is 5878656, while the sum is 61.

The square root of 999987280 is about 31622.5754801850. The cubic root of 999987280 is about 999.9957599820.

It can be divided in two parts, 9999 and 87280, that added together give a palindrome (97279).

The spelling of 999987280 in words is "nine hundred ninety-nine million, nine hundred eighty-seven thousand, two hundred eighty".