61222781 has 2 divisors, whose sum is σ = 61222782. Its totient is φ = 61222780.

The previous prime is 61222771. The next prime is 61222789. The reversal of 61222781 is 18722216.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60310756 + 912025 = 7766^2 + 955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61222781 is a prime.

It is a super-2 number, since 2×61222781² = 7496457826747922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61222789) 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, 30611390 + 30611391.

It is an arithmetic number, because the mean of its divisors is an integer number (30611391).

Almost surely, 2^61222781 is an apocalyptic number.

It is an amenable number.

61222781 is a deficient number, since it is larger than the sum of its proper divisors (1).

61222781 is an equidigital number, since it uses as much as digits as its factorization.

61222781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 29.

The square root of 61222781 is about 7824.4987698894. The cubic root of 61222781 is about 394.1283583778.

Adding to 61222781 its reverse (18722216), we get a palindrome (79944997).

The spelling of 61222781 in words is "sixty-one million, two hundred twenty-two thousand, seven hundred eighty-one".