5661221639 has 2 divisors, whose sum is σ = 5661221640. Its totient is φ = 5661221638.

The previous prime is 5661221611. The next prime is 5661221681. The reversal of 5661221639 is 9361221665.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5661221639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 5661221596 and 5661221605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5661221039) 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, 2830610819 + 2830610820.

It is an arithmetic number, because the mean of its divisors is an integer number (2830610820).

Almost surely, 2^5661221639 is an apocalyptic number.

5661221639 is a deficient number, since it is larger than the sum of its proper divisors (1).

5661221639 is an equidigital number, since it uses as much as digits as its factorization.

5661221639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 41.

The square root of 5661221639 is about 75241.0900971005. The cubic root of 5661221639 is about 1782.2558654882.

The spelling of 5661221639 in words is "five billion, six hundred sixty-one million, two hundred twenty-one thousand, six hundred thirty-nine".