28491020 has 48 divisors (see below), whose sum is σ = 62935488. Its totient is φ = 10813440.

The previous prime is 28491019. The next prime is 28491037. The reversal of 28491020 is 2019482.

It is a super-4 number, since 4×28491020⁴ (a number of 31 digits) contains 4444 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110732 + ... + 110988.

It is an arithmetic number, because the mean of its divisors is an integer number (1311156).

Almost surely, 2^28491020 is an apocalyptic number.

28491020 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 28491020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31467744).

28491020 is an abundant number, since it is smaller than the sum of its proper divisors (34444468).

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

28491020 is a wasteful number, since it uses less digits than its factorization.

28491020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530 (or 528 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 28491020 is about 5337.6980056950. The cubic root of 28491020 is about 305.4236520605.

The spelling of 28491020 in words is "twenty-eight million, four hundred ninety-one thousand, twenty".