28190820 has 48 divisors (see below), whose sum is σ = 90211968. Its totient is φ = 6443520.

The previous prime is 28190809. The next prime is 28190837. The reversal of 28190820 is 2809182.

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

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, 33141 + ... + 33980.

It is an arithmetic number, because the mean of its divisors is an integer number (1879416).

Almost surely, 2^28190820 is an apocalyptic number.

28190820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28190820 is an abundant number, since it is smaller than the sum of its proper divisors (62021148).

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

28190820 is a wasteful number, since it uses less digits than its factorization.

28190820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67140 (or 67138 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 30.

The square root of 28190820 is about 5309.5028015813. The cubic root of 28190820 is about 304.3471478660.

The spelling of 28190820 in words is "twenty-eight million, one hundred ninety thousand, eight hundred twenty".