28661920 has 96 divisors (see below), whose sum is σ = 78357888. Its totient is φ = 9704448.

The previous prime is 28661903. The next prime is 28661953. The reversal of 28661920 is 2916682.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175759 + ... + 175921.

It is an arithmetic number, because the mean of its divisors is an integer number (816228).

Almost surely, 2^28661920 is an apocalyptic number.

28661920 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 28661920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39178944).

28661920 is an abundant number, since it is smaller than the sum of its proper divisors (49695968).

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

28661920 is a wasteful number, since it uses less digits than its factorization.

28661920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 28661920 is about 5353.6828445473. The cubic root of 28661920 is about 306.0331175799.

The spelling of 28661920 in words is "twenty-eight million, six hundred sixty-one thousand, nine hundred twenty".