28731930 has 16 divisors (see below), whose sum is σ = 68956704. Its totient is φ = 7661840.

The previous prime is 28731919. The next prime is 28731931. The reversal of 28731930 is 3913782.

It is a junction number, because it is equal to n+sod(n) for n = 28731891 and 28731900.

It is not an unprimeable number, because it can be changed into a prime (28731931) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 478836 + ... + 478895.

It is an arithmetic number, because the mean of its divisors is an integer number (4309794).

Almost surely, 2^28731930 is an apocalyptic number.

28731930 is an abundant number, since it is smaller than the sum of its proper divisors (40224774).

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

28731930 is a wasteful number, since it uses less digits than its factorization.

28731930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957741.

The product of its (nonzero) digits is 9072, while the sum is 33.

The square root of 28731930 is about 5360.2173463396. The cubic root of 28731930 is about 306.2820885438.

The spelling of 28731930 in words is "twenty-eight million, seven hundred thirty-one thousand, nine hundred thirty".