28021081 has 8 divisors (see below), whose sum is σ = 31314528. Its totient is φ = 24852000.

The previous prime is 28021057. The next prime is 28021087. The reversal of 28021081 is 18012082.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28021081 - 2⁹ = 28020569 is a prime.

It is a super-2 number, since 2×28021081² = 1570361960817122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28021087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30615 + ... + 31516.

It is an arithmetic number, because the mean of its divisors is an integer number (3914316).

Almost surely, 2^28021081 is an apocalyptic number.

It is an amenable number.

28021081 is a deficient number, since it is larger than the sum of its proper divisors (3293447).

28021081 is a wasteful number, since it uses less digits than its factorization.

28021081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62183.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 28021081 is about 5293.4942145997. The cubic root of 28021081 is about 303.7350856084.

It can be divided in two parts, 2802 and 1081, that added together give a palindrome (3883).

The spelling of 28021081 in words is "twenty-eight million, twenty-one thousand, eighty-one".