28975981 has 2 divisors, whose sum is σ = 28975982. Its totient is φ = 28975980.

The previous prime is 28975957. The next prime is 28975987. The reversal of 28975981 is 18957982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 25857225 + 3118756 = 5085^2 + 1766^2 .

It is a cyclic number.

It is not a de Polignac number, because 28975981 - 2⁷ = 28975853 is a prime.

It is a super-2 number, since 2×28975981² = 1679214949824722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28975987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14487990 + 14487991.

It is an arithmetic number, because the mean of its divisors is an integer number (14487991).

Almost surely, 2^28975981 is an apocalyptic number.

It is an amenable number.

28975981 is a deficient number, since it is larger than the sum of its proper divisors (1).

28975981 is an equidigital number, since it uses as much as digits as its factorization.

28975981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 362880, while the sum is 49.

The square root of 28975981 is about 5382.9342370124. The cubic root of 28975981 is about 307.1468384763.

The spelling of 28975981 in words is "twenty-eight million, nine hundred seventy-five thousand, nine hundred eighty-one".