28740720 has 80 divisors (see below), whose sum is σ = 91994112. Its totient is φ = 7415040.

The previous prime is 28740709. The next prime is 28740721. The reversal of 28740720 is 2704782.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×28740720² = 1652057972236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28740721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5509 + ... + 9371.

Almost surely, 2^28740720 is an apocalyptic number.

28740720 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 28740720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45997056).

28740720 is an abundant number, since it is smaller than the sum of its proper divisors (63253392).

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

28740720 is a wasteful number, since it uses less digits than its factorization.

28740720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3910 (or 3904 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 28740720 is about 5361.0372130773. The cubic root of 28740720 is about 306.3133191302.

The spelling of 28740720 in words is "twenty-eight million, seven hundred forty thousand, seven hundred twenty".