28720476 has 72 divisors (see below), whose sum is σ = 77168000. Its totient is φ = 8981280.

The previous prime is 28720453. The next prime is 28720487. The reversal of 28720476 is 67402782.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 28720476.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136011 + ... + 136221.

Almost surely, 2^28720476 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28720476, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38584000).

28720476 is an abundant number, since it is smaller than the sum of its proper divisors (48447524).

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

28720476 is a wasteful number, since it uses less digits than its factorization.

28720476 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439 (or 434 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

The square root of 28720476 is about 5359.1488130113. The cubic root of 28720476 is about 306.2413832922.

The spelling of 28720476 in words is "twenty-eight million, seven hundred twenty thousand, four hundred seventy-six".