9999972 has 36 divisors (see below), whose sum is σ = 25409020.
Its totient is φ = 3316032.
The previous prime is 9999971. The next prime is 9999973. The reversal of 9999972 is 2799999.
It is an interprime number because it is at equal distance from previous prime (9999971) and next prime (9999973).
It can be written as a sum of positive squares in 2 ways, for example, as 4691556 + 5308416 = 2166^2 + 2304^2
It is a tau number, because it is divible by the number of its divisors (36).
It is a nialpdrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (9999971) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7638 + ... + 8850.
Almost surely, 29999972 is an apocalyptic number.
It is an amenable number.
9999972 is an abundant number, since it is smaller than the sum of its proper divisors (15409048).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9999972 is a wasteful number, since it uses less digits than its factorization.
9999972 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 1452 (or 1447 counting only the distinct ones).
The product of its digits is 826686, while the sum is 54.
The square root of 9999972 is about 3162.2732329766.
The cubic root of 9999972 is about 215.4432679224.
It can be divided in two parts, 999997 and 2, that added together give a palindrome (999999).
The spelling of 9999972 in words is "nine million, nine hundred ninety-nine thousand, nine hundred seventy-two".