28181501 has 2 divisors, whose sum is σ = 28181502. Its totient is φ = 28181500.

The previous prime is 28181471. The next prime is 28181513. The reversal of 28181501 is 10518182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22080601 + 6100900 = 4699^2 + 2470^2 .

It is a cyclic number.

It is not a de Polignac number, because 28181501 - 2¹⁴ = 28165117 is a prime.

It is a super-2 number, since 2×28181501² = 1588393997226002, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28181551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14090750 + 14090751.

It is an arithmetic number, because the mean of its divisors is an integer number (14090751).

Almost surely, 2^28181501 is an apocalyptic number.

It is an amenable number.

28181501 is a deficient number, since it is larger than the sum of its proper divisors (1).

28181501 is an equidigital number, since it uses as much as digits as its factorization.

28181501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 26.

The square root of 28181501 is about 5308.6251515812. The cubic root of 28181501 is about 304.3136082994.

Adding to 28181501 its reverse (10518182), we get a palindrome (38699683).

It can be divided in two parts, 28181 and 501, that added together give a palindrome (28682).

The spelling of 28181501 in words is "twenty-eight million, one hundred eighty-one thousand, five hundred one".