61868561 has 2 divisors, whose sum is σ = 61868562. Its totient is φ = 61868560.

The previous prime is 61868557. The next prime is 61868563. The reversal of 61868561 is 16586816.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51208336 + 10660225 = 7156^2 + 3265^2 .

It is a cyclic number.

It is not a de Polignac number, because 61868561 - 2² = 61868557 is a prime.

Together with 61868563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (61868563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30934280 + 30934281.

It is an arithmetic number, because the mean of its divisors is an integer number (30934281).

Almost surely, 2^61868561 is an apocalyptic number.

It is an amenable number.

61868561 is a deficient number, since it is larger than the sum of its proper divisors (1).

61868561 is an equidigital number, since it uses as much as digits as its factorization.

61868561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 41.

The square root of 61868561 is about 7865.6570609200. The cubic root of 61868561 is about 395.5092742104.

The spelling of 61868561 in words is "sixty-one million, eight hundred sixty-eight thousand, five hundred sixty-one".