999972 has 48 divisors (see below), whose sum is σ = 2661120. Its totient is φ = 324576.

The previous prime is 999961. The next prime is 999979. The reversal of 999972 is 279999.

999972 is nontrivially palindromic in base 11.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (999979) 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, 4978 + ... + 5174.

It is an arithmetic number, because the mean of its divisors is an integer number (55440).

2⁹⁹⁹⁹⁷² is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 999972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1330560).

999972 is an abundant number, since it is smaller than the sum of its proper divisors (1661148).

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

999972 is a wasteful number, since it uses less digits than its factorization.

999972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 249 counting only the distinct ones).

The product of its digits is 91854, while the sum is 45.

The square root of 999972 is about 999.9859999020. The cubic root of 999972 is about 99.9990666580. Note that the first 3 decimals are identical.

It can be divided in two parts, 99997 and 2, that added together give a palindrome (99999).

The spelling of 999972 in words is "nine hundred ninety-nine thousand, nine hundred seventy-two".