21441220061 has 2 divisors, whose sum is σ = 21441220062. Its totient is φ = 21441220060.

The previous prime is 21441220051. The next prime is 21441220133. The reversal of 21441220061 is 16002214412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15458197561 + 5983022500 = 124331^2 + 77350^2 .

It is a cyclic number.

It is not a de Polignac number, because 21441220061 - 2¹⁸ = 21440957917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21441220051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10720610030 + 10720610031.

It is an arithmetic number, because the mean of its divisors is an integer number (10720610031).

Almost surely, 2^21441220061 is an apocalyptic number.

It is an amenable number.

21441220061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21441220061 is an equidigital number, since it uses as much as digits as its factorization.

21441220061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 23.

Adding to 21441220061 its reverse (16002214412), we get a palindrome (37443434473).

The spelling of 21441220061 in words is "twenty-one billion, four hundred forty-one million, two hundred twenty thousand, sixty-one".