28021312 has 56 divisors (see below), whose sum is σ = 61886592. Its totient is φ = 12480000.

The previous prime is 28021309. The next prime is 28021313. The reversal of 28021312 is 21312082.

It is a self number, because there is not a number n which added to its sum of digits gives 28021312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28021313) 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, 36937 + ... + 37687.

Almost surely, 2^28021312 is an apocalyptic number.

28021312 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28021312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30943296).

28021312 is an abundant number, since it is smaller than the sum of its proper divisors (33865280).

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

28021312 is a wasteful number, since it uses less digits than its factorization.

28021312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827 (or 817 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 28021312 is about 5293.5160337908. The cubic root of 28021312 is about 303.7359202492.

Adding to 28021312 its reverse (21312082), we get a palindrome (49333394).

It can be divided in two parts, 2802 and 1312, that added together give a palindrome (4114).

The spelling of 28021312 in words is "twenty-eight million, twenty-one thousand, three hundred twelve".