61643321 has 2 divisors, whose sum is σ = 61643322. Its totient is φ = 61643320.

The previous prime is 61643297. The next prime is 61643333. The reversal of 61643321 is 12334616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56851600 + 4791721 = 7540^2 + 2189^2 .

It is a cyclic number.

It is not a de Polignac number, because 61643321 - 2¹⁰ = 61642297 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (61643371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30821660 + 30821661.

It is an arithmetic number, because the mean of its divisors is an integer number (30821661).

Almost surely, 2^61643321 is an apocalyptic number.

It is an amenable number.

61643321 is a deficient number, since it is larger than the sum of its proper divisors (1).

61643321 is an equidigital number, since it uses as much as digits as its factorization.

61643321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 26.

The square root of 61643321 is about 7851.3260663406. The cubic root of 61643321 is about 395.0287240768.

Adding to 61643321 its reverse (12334616), we get a palindrome (73977937).

The spelling of 61643321 in words is "sixty-one million, six hundred forty-three thousand, three hundred twenty-one".