28572981 has 4 divisors (see below), whose sum is σ = 38097312. Its totient is φ = 19048652.

The previous prime is 28572977. The next prime is 28572983. The reversal of 28572981 is 18927582.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28572981 - 2² = 28572977 is a prime.

It is a super-2 number, since 2×28572981² = 1632830486452722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28572983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4762161 + ... + 4762166.

It is an arithmetic number, because the mean of its divisors is an integer number (9524328).

Almost surely, 2^28572981 is an apocalyptic number.

It is an amenable number.

28572981 is a deficient number, since it is larger than the sum of its proper divisors (9524331).

28572981 is an equidigital number, since it uses as much as digits as its factorization.

28572981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9524330.

The product of its digits is 80640, while the sum is 42.

The square root of 28572981 is about 5345.3700526718. The cubic root of 28572981 is about 305.7162455631.

The spelling of 28572981 in words is "twenty-eight million, five hundred seventy-two thousand, nine hundred eighty-one".