28661257 has 2 divisors, whose sum is σ = 28661258. Its totient is φ = 28661256.

The previous prime is 28661221. The next prime is 28661317. The reversal of 28661257 is 75216682.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23001616 + 5659641 = 4796^2 + 2379^2 .

It is a cyclic number.

It is not a de Polignac number, because 28661257 - 2¹⁵ = 28628489 is a prime.

It is not a weakly prime, because it can be changed into another prime (28661057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14330628 + 14330629.

It is an arithmetic number, because the mean of its divisors is an integer number (14330629).

Almost surely, 2^28661257 is an apocalyptic number.

It is an amenable number.

28661257 is a deficient number, since it is larger than the sum of its proper divisors (1).

28661257 is an equidigital number, since it uses as much as digits as its factorization.

28661257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 37.

The square root of 28661257 is about 5353.6209241970. The cubic root of 28661257 is about 306.0307578691.

The spelling of 28661257 in words is "twenty-eight million, six hundred sixty-one thousand, two hundred fifty-seven".