28891380 has 144 divisors (see below), whose sum is σ = 97445376. Its totient is φ = 6370560.

The previous prime is 28891367. The next prime is 28891403. The reversal of 28891380 is 8319882.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 90982 + ... + 91298.

It is an arithmetic number, because the mean of its divisors is an integer number (676704).

Almost surely, 2^28891380 is an apocalyptic number.

28891380 is a gapful number since it is divisible by the number (20) 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 28891380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48722688).

28891380 is an abundant number, since it is smaller than the sum of its proper divisors (68553996).

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

28891380 is a wasteful number, since it uses less digits than its factorization.

28891380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 39.

The square root of 28891380 is about 5375.0702320993. The cubic root of 28891380 is about 306.8476221457.

The spelling of 28891380 in words is "twenty-eight million, eight hundred ninety-one thousand, three hundred eighty".