28220436 has 36 divisors (see below), whose sum is σ = 71803732. Its totient is φ = 9345024.

The previous prime is 28220431. The next prime is 28220443. The reversal of 28220436 is 63402282.

28220436 is a `hidden beast` number, since 2 + 8 + 220 + 436 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9036036 + 19184400 = 3006^2 + 4380^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28220431) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3156 + ... + 8148.

Almost surely, 2^28220436 is an apocalyptic number.

It is an amenable number.

28220436 is an abundant number, since it is smaller than the sum of its proper divisors (43583296).

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

28220436 is a wasteful number, since it uses less digits than its factorization.

28220436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5160 (or 5155 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 28220436 is about 5312.2910311842. The cubic root of 28220436 is about 304.4536883469.

The spelling of 28220436 in words is "twenty-eight million, two hundred twenty thousand, four hundred thirty-six".