7821312 has 96 divisors (see below), whose sum is σ = 22276800. Its totient is φ = 2433024.

The previous prime is 7821301. The next prime is 7821323. The reversal of 7821312 is 2131287.

It is an interprime number because it is at equal distance from previous prime (7821301) and next prime (7821323).

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×7821312² = 122345842802688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116703 + ... + 116769.

It is an arithmetic number, because the mean of its divisors is an integer number (232050).

Almost surely, 2^7821312 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 7821312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11138400).

7821312 is an abundant number, since it is smaller than the sum of its proper divisors (14455488).

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

7821312 is a wasteful number, since it uses less digits than its factorization.

7821312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111 (or 91 counting only the distinct ones).

The product of its digits is 672, while the sum is 24.

The square root of 7821312 is about 2796.6608661044. The cubic root of 7821312 is about 198.4997070806.

Adding to 7821312 its reverse (2131287), we get a palindrome (9952599).

The spelling of 7821312 in words is "seven million, eight hundred twenty-one thousand, three hundred twelve".