28728990 has 24 divisors (see below), whose sum is σ = 74695608. Its totient is φ = 7661040.

The previous prime is 28728989. The next prime is 28728991. The reversal of 28728990 is 9982782.

28728990 is a `hidden beast` number, since 287 + 289 + 90 = 666.

It is an interprime number because it is at equal distance from previous prime (28728989) and next prime (28728991).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728991) 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, 159516 + ... + 159695.

It is an arithmetic number, because the mean of its divisors is an integer number (3112317).

Almost surely, 2^28728990 is an apocalyptic number.

28728990 is an abundant number, since it is smaller than the sum of its proper divisors (45966618).

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

28728990 is a wasteful number, since it uses less digits than its factorization.

28728990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319224 (or 319221 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 28728990 is about 5359.9430967129. The cubic root of 28728990 is about 306.2716413972.

The spelling of 28728990 in words is "twenty-eight million, seven hundred twenty-eight thousand, nine hundred ninety".