28631780 has 48 divisors (see below), whose sum is σ = 63745920. Its totient is φ = 10779648.

The previous prime is 28631777. The next prime is 28631797. The reversal of 28631780 is 8713682.

It is a self number, because there is not a number n which added to its sum of digits gives 28631780.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 30356 + ... + 31284.

It is an arithmetic number, because the mean of its divisors is an integer number (1328040).

Almost surely, 2^28631780 is an apocalyptic number.

28631780 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 28631780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31872960).

28631780 is an abundant number, since it is smaller than the sum of its proper divisors (35114140).

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

28631780 is a wasteful number, since it uses less digits than its factorization.

28631780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028 (or 1026 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 28631780 is about 5350.8672194328. The cubic root of 28631780 is about 305.9258082623.

The spelling of 28631780 in words is "twenty-eight million, six hundred thirty-one thousand, seven hundred eighty".