21779141 has 2 divisors, whose sum is σ = 21779142. Its totient is φ = 21779140.

The previous prime is 21779129. The next prime is 21779161. The reversal of 21779141 is 14197712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20666116 + 1113025 = 4546^2 + 1055^2 .

It is a cyclic number.

It is not a de Polignac number, because 21779141 - 2¹⁰ = 21778117 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21779098 and 21779107.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21779161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10889570 + 10889571.

It is an arithmetic number, because the mean of its divisors is an integer number (10889571).

Almost surely, 2^21779141 is an apocalyptic number.

It is an amenable number.

21779141 is a deficient number, since it is larger than the sum of its proper divisors (1).

21779141 is an equidigital number, since it uses as much as digits as its factorization.

21779141 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3528, while the sum is 32.

The square root of 21779141 is about 4666.8127239048. The cubic root of 21779141 is about 279.2631177036.

The spelling of 21779141 in words is "twenty-one million, seven hundred seventy-nine thousand, one hundred forty-one".