999999972 has 48 divisors (see below), whose sum is σ = 2641524480.
Its totient is φ = 327042144.
The previous prime is 999999937. The next prime is 1000000007. The reversal of 999999972 is 279999999.
It is an interprime number because it is at equal distance from previous prime (999999937) and next prime (1000000007).
It is a nialpdrome in base 10.
It is a self number, because there is not a number n which added to its sum of digits gives 999999972.
It is an unprimeable number.
It is a pernicious number, because its binary representation contains a prime number (17) of ones.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81628 + ... + 93075.
It is an arithmetic number, because the mean of its divisors is an integer number (55031760).
Almost surely, 2999999972 is an apocalyptic number.
It is an amenable number.
999999972 is an abundant number, since it is smaller than the sum of its proper divisors (1641524508).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
999999972 is a wasteful number, since it uses less digits than its factorization.
999999972 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 174769 (or 174761 counting only the distinct ones).
The product of its digits is 66961566, while the sum is 72.
The square root of 999999972 is about 31622.7761589649.
The cubic root of 999999972 is about 999.9999906667.
Note that the first 5 decimals are identical.
It can be divided in two parts, 99999997 and 2, that added together give a palindrome (99999999).
The spelling of 999999972 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred seventy-two".