28491240 has 64 divisors (see below), whose sum is σ = 85924800. Its totient is φ = 7557632.

The previous prime is 28491233. The next prime is 28491283. The reversal of 28491240 is 4219482.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 28491198 and 28491207.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27451 + ... + 28469.

It is an arithmetic number, because the mean of its divisors is an integer number (1342575).

Almost surely, 2^28491240 is an apocalyptic number.

28491240 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 28491240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42962400).

28491240 is an abundant number, since it is smaller than the sum of its proper divisors (57433560).

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

28491240 is a wasteful number, since it uses less digits than its factorization.

28491240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 28491240 is about 5337.7186137900. The cubic root of 28491240 is about 305.4244381916.

The spelling of 28491240 in words is "twenty-eight million, four hundred ninety-one thousand, two hundred forty".