28220481 has 10 divisors (see below), whose sum is σ = 42156642. Its totient is φ = 18813600.

The previous prime is 28220473. The next prime is 28220497. The reversal of 28220481 is 18402282.

It can be written as a sum of positive squares in only one way, i.e., 16769025 + 11451456 = 4095^2 + 3384^2 .

It is not a de Polignac number, because 28220481 - 2³ = 28220473 is a prime.

It is a super-2 number, since 2×28220481² = 1592791095742722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (28220411) 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, 174120 + ... + 174281.

Almost surely, 2^28220481 is an apocalyptic number.

It is an amenable number.

28220481 is a deficient number, since it is larger than the sum of its proper divisors (13936161).

28220481 is an equidigital number, since it uses as much as digits as its factorization.

28220481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348413 (or 348404 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 28220481 is about 5312.2952666432. The cubic root of 28220481 is about 304.4538501730.

The spelling of 28220481 in words is "twenty-eight million, two hundred twenty thousand, four hundred eighty-one".