28032981 has 4 divisors (see below), whose sum is σ = 37377312. Its totient is φ = 18688652.

The previous prime is 28032973. The next prime is 28033007. The reversal of 28032981 is 18923082.

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 28032981 - 2³ = 28032973 is a prime.

It is a super-2 number, since 2×28032981² = 1571696047492722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28032481) 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, 4672161 + ... + 4672166.

It is an arithmetic number, because the mean of its divisors is an integer number (9344328).

Almost surely, 2^28032981 is an apocalyptic number.

It is an amenable number.

28032981 is a deficient number, since it is larger than the sum of its proper divisors (9344331).

28032981 is an equidigital number, since it uses as much as digits as its factorization.

28032981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9344330.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 28032981 is about 5294.6181165406. The cubic root of 28032981 is about 303.7780762884.

The spelling of 28032981 in words is "twenty-eight million, thirty-two thousand, nine hundred eighty-one".