28636578 has 32 divisors (see below), whose sum is σ = 64432320. Its totient is φ = 9544068.

The previous prime is 28636571. The next prime is 28636603. The reversal of 28636578 is 87563682.

28636578 is a `hidden beast` number, since 2 + 8 + 636 + 5 + 7 + 8 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28636571) 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, 1101 + ... + 7647.

It is an arithmetic number, because the mean of its divisors is an integer number (2013510).

Almost surely, 2^28636578 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28636578, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32216160).

28636578 is an abundant number, since it is smaller than the sum of its proper divisors (35795742).

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

28636578 is an frugal number, since it uses more digits than its factorization.

28636578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6570 (or 6552 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 28636578 is about 5351.3155391922. The cubic root of 28636578 is about 305.9428959186.

It can be divided in two parts, 286 and 36578, that added together give a square (36864 = 192²).

The spelling of 28636578 in words is "twenty-eight million, six hundred thirty-six thousand, five hundred seventy-eight".