6221061661 has 2 divisors, whose sum is σ = 6221061662. Its totient is φ = 6221061660.

The previous prime is 6221061647. The next prime is 6221061673. The reversal of 6221061661 is 1661601226.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4355340025 + 1865721636 = 65995^2 + 43194^2 .

It is a cyclic number.

It is not a de Polignac number, because 6221061661 - 2¹³ = 6221053469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6221061631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3110530830 + 3110530831.

It is an arithmetic number, because the mean of its divisors is an integer number (3110530831).

Almost surely, 2^6221061661 is an apocalyptic number.

It is an amenable number.

6221061661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6221061661 is an equidigital number, since it uses as much as digits as its factorization.

6221061661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 6221061661 is about 78873.7070321917. The cubic root of 6221061661 is about 1839.1684235574.

Adding to 6221061661 its reverse (1661601226), we get a palindrome (7882662887).

The spelling of 6221061661 in words is "six billion, two hundred twenty-one million, sixty-one thousand, six hundred sixty-one".