28724140 has 12 divisors (see below), whose sum is σ = 60320736. Its totient is φ = 11489648.

The previous prime is 28724117. The next prime is 28724147. The reversal of 28724140 is 4142782.

It is a junction number, because it is equal to n+sod(n) for n = 28724099 and 28724108.

It is not an unprimeable number, because it can be changed into a prime (28724147) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 718084 + ... + 718123.

It is an arithmetic number, because the mean of its divisors is an integer number (5026728).

Almost surely, 2^28724140 is an apocalyptic number.

28724140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28724140 is an abundant number, since it is smaller than the sum of its proper divisors (31596596).

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

28724140 is a wasteful number, since it uses less digits than its factorization.

28724140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1436216 (or 1436214 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 28724140 is about 5359.4906474403. The cubic root of 28724140 is about 306.2544056009.

The spelling of 28724140 in words is "twenty-eight million, seven hundred twenty-four thousand, one hundred forty".