28688724 has 36 divisors (see below), whose sum is σ = 76786164. Its totient is φ = 9000192.

The previous prime is 28688717. The next prime is 28688729. The reversal of 28688724 is 42788682.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9922500 + 18766224 = 3150^2 + 4332^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 28688724.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28688729) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22827 + ... + 24050.

It is an arithmetic number, because the mean of its divisors is an integer number (2132949).

Almost surely, 2^28688724 is an apocalyptic number.

It is an amenable number.

28688724 is an abundant number, since it is smaller than the sum of its proper divisors (48097440).

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

28688724 is a wasteful number, since it uses less digits than its factorization.

28688724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46904 (or 46899 counting only the distinct ones).

The product of its digits is 344064, while the sum is 45.

The square root of 28688724 is about 5356.1855830432. The cubic root of 28688724 is about 306.1284863473.

The spelling of 28688724 in words is "twenty-eight million, six hundred eighty-eight thousand, seven hundred twenty-four".