28620864 has 70 divisors (see below), whose sum is σ = 84856574. Its totient is φ = 9538560.

The previous prime is 28620863. The next prime is 28620871. The reversal of 28620864 is 46802682.

28620864 is a `hidden beast` number, since 28 + 620 + 8 + 6 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 21902400 + 6718464 = 4680^2 + 2592^2 .

It is a super-3 number, since 3×28620864³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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

It is not an unprimeable number, because it can be changed into a prime (28620863) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2424 + ... + 7944.

Almost surely, 2^28620864 is an apocalyptic number.

28620864 is a gapful number since it is divisible by the number (24) 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 28620864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42428287).

28620864 is an abundant number, since it is smaller than the sum of its proper divisors (56235710).

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

28620864 is an equidigital number, since it uses as much as digits as its factorization.

28620864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5545 (or 5526 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 28620864 is about 5349.8471006189. The cubic root of 28620864 is about 305.8869247721.

The spelling of 28620864 in words is "twenty-eight million, six hundred twenty thousand, eight hundred sixty-four".