28910920 has 32 divisors (see below), whose sum is σ = 65947320. Its totient is φ = 11404800.

The previous prime is 28910909. The next prime is 28910923. The reversal of 28910920 is 2901982.

It can be written as a sum of positive squares in 4 ways, for example, as 28366276 + 544644 = 5326^2 + 738^2 .

It is not an unprimeable number, because it can be changed into a prime (28910923) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2031 + ... + 7870.

Almost surely, 2^28910920 is an apocalyptic number.

28910920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28910920 is an abundant number, since it is smaller than the sum of its proper divisors (37036400).

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

28910920 is a wasteful number, since it uses less digits than its factorization.

28910920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9985 (or 9981 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 28910920 is about 5376.8875755403. The cubic root of 28910920 is about 306.9167829281.

The spelling of 28910920 in words is "twenty-eight million, nine hundred ten thousand, nine hundred twenty".