28770520 has 64 divisors (see below), whose sum is σ = 67767840. Its totient is φ = 10982400.

The previous prime is 28770517. The next prime is 28770551. The reversal of 28770520 is 2507782.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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, 86755 + ... + 87085.

Almost surely, 2^28770520 is an apocalyptic number.

28770520 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 28770520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33883920).

28770520 is an abundant number, since it is smaller than the sum of its proper divisors (38997320).

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

28770520 is a wasteful number, since it uses less digits than its factorization.

28770520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436 (or 432 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 31.

The square root of 28770520 is about 5363.8158059352. The cubic root of 28770520 is about 306.4191502050.

It can be divided in two parts, 287 and 70520, that added together give a palindrome (70807).

The spelling of 28770520 in words is "twenty-eight million, seven hundred seventy thousand, five hundred twenty".