21802141 has 2 divisors, whose sum is σ = 21802142. Its totient is φ = 21802140.

The previous prime is 21802129. The next prime is 21802159. The reversal of 21802141 is 14120812.

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., 18096516 + 3705625 = 4254^2 + 1925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21802141 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21802541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10901070 + 10901071.

It is an arithmetic number, because the mean of its divisors is an integer number (10901071).

Almost surely, 2^21802141 is an apocalyptic number.

It is an amenable number.

21802141 is a deficient number, since it is larger than the sum of its proper divisors (1).

21802141 is an equidigital number, since it uses as much as digits as its factorization.

21802141 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21802141 is about 4669.2762822519. The cubic root of 21802141 is about 279.3613889807.

Adding to 21802141 its reverse (14120812), we get a palindrome (35922953).

The spelling of 21802141 in words is "twenty-one million, eight hundred two thousand, one hundred forty-one".