28491637 has 2 divisors, whose sum is σ = 28491638. Its totient is φ = 28491636.

The previous prime is 28491629. The next prime is 28491647. The reversal of 28491637 is 73619482.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21169201 + 7322436 = 4601^2 + 2706^2 .

It is a cyclic number.

It is not a de Polignac number, because 28491637 - 2³ = 28491629 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28491637.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28491647) 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 as a sum of consecutive naturals, namely, 14245818 + 14245819.

It is an arithmetic number, because the mean of its divisors is an integer number (14245819).

Almost surely, 2^28491637 is an apocalyptic number.

It is an amenable number.

28491637 is a deficient number, since it is larger than the sum of its proper divisors (1).

28491637 is an equidigital number, since it uses as much as digits as its factorization.

28491637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 40.

The square root of 28491637 is about 5337.7558018328. The cubic root of 28491637 is about 305.4258567907.

The spelling of 28491637 in words is "twenty-eight million, four hundred ninety-one thousand, six hundred thirty-seven".