28911940 has 24 divisors (see below), whose sum is σ = 60822720. Its totient is φ = 11544288.

The previous prime is 28911919. The next prime is 28911941. The reversal of 28911940 is 4911982.

It is a junction number, because it is equal to n+sod(n) for n = 28911896 and 28911905.

It is not an unprimeable number, because it can be changed into a prime (28911941) 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, 15919 + ... + 17641.

It is an arithmetic number, because the mean of its divisors is an integer number (2534280).

Almost surely, 2^28911940 is an apocalyptic number.

28911940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28911940 is an abundant number, since it is smaller than the sum of its proper divisors (31910780).

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

28911940 is a wasteful number, since it uses less digits than its factorization.

28911940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2571 (or 2569 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 28911940 is about 5376.9824251154. The cubic root of 28911940 is about 306.9203923075.

The spelling of 28911940 in words is "twenty-eight million, nine hundred eleven thousand, nine hundred forty".