28744981 has 4 divisors (see below), whose sum is σ = 28837132. Its totient is φ = 28652832.

The previous prime is 28744957. The next prime is 28744993. The reversal of 28744981 is 18944782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2387025 + 26357956 = 1545^2 + 5134^2 .

It is a cyclic number.

It is not a de Polignac number, because 28744981 - 2⁵ = 28744949 is a prime.

It is a super-2 number, since 2×28744981² = 1652547865380722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28744951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45606 + ... + 46231.

It is an arithmetic number, because the mean of its divisors is an integer number (7209283).

Almost surely, 2^28744981 is an apocalyptic number.

It is an amenable number.

28744981 is a deficient number, since it is larger than the sum of its proper divisors (92151).

28744981 is an equidigital number, since it uses as much as digits as its factorization.

28744981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92150.

The product of its digits is 129024, while the sum is 43.

The square root of 28744981 is about 5361.4346027906. The cubic root of 28744981 is about 306.3284560341.

The spelling of 28744981 in words is "twenty-eight million, seven hundred forty-four thousand, nine hundred eighty-one".