28961281 has 2 divisors, whose sum is σ = 28961282. Its totient is φ = 28961280.

The previous prime is 28961243. The next prime is 28961287. The reversal of 28961281 is 18216982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19713600 + 9247681 = 4440^2 + 3041^2 .

It is a cyclic number.

It is not a de Polignac number, because 28961281 - 2¹⁷ = 28830209 is a prime.

It is a super-2 number, since 2×28961281² = 1677511594321922, which contains 22 as substring.

It is equal to p_1797427 and since 28961281 and 1797427 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28961281.

It is not a weakly prime, because it can be changed into another prime (28961287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14480640 + 14480641.

It is an arithmetic number, because the mean of its divisors is an integer number (14480641).

Almost surely, 2^28961281 is an apocalyptic number.

It is an amenable number.

28961281 is a deficient number, since it is larger than the sum of its proper divisors (1).

28961281 is an equidigital number, since it uses as much as digits as its factorization.

28961281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 37.

The square root of 28961281 is about 5381.5686374885. The cubic root of 28961281 is about 307.0948894469.

The spelling of 28961281 in words is "twenty-eight million, nine hundred sixty-one thousand, two hundred eighty-one".