28307940 has 96 divisors (see below), whose sum is σ = 84139776. Its totient is φ = 7096320.

The previous prime is 28307933. The next prime is 28307947. The reversal of 28307940 is 4970382.

It is an interprime number because it is at equal distance from previous prime (28307933) and next prime (28307947).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28307947) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 100600 + ... + 100880.

It is an arithmetic number, because the mean of its divisors is an integer number (876456).

Almost surely, 2^28307940 is an apocalyptic number.

28307940 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 28307940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42069888).

28307940 is an abundant number, since it is smaller than the sum of its proper divisors (55831836).

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

28307940 is a wasteful number, since it uses less digits than its factorization.

28307940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389 (or 387 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 28307940 is about 5320.5206512145. The cubic root of 28307940 is about 304.7680400628.

The spelling of 28307940 in words is "twenty-eight million, three hundred seven thousand, nine hundred forty".