61561321 has 2 divisors, whose sum is σ = 61561322. Its totient is φ = 61561320.

The previous prime is 61561307. The next prime is 61561327. The reversal of 61561321 is 12316516.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57214096 + 4347225 = 7564^2 + 2085^2 .

It is a cyclic number.

It is not a de Polignac number, because 61561321 - 2⁵ = 61561289 is a prime.

It is not a weakly prime, because it can be changed into another prime (61561327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30780660 + 30780661.

It is an arithmetic number, because the mean of its divisors is an integer number (30780661).

Almost surely, 2^61561321 is an apocalyptic number.

It is an amenable number.

61561321 is a deficient number, since it is larger than the sum of its proper divisors (1).

61561321 is an equidigital number, since it uses as much as digits as its factorization.

61561321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 25.

The square root of 61561321 is about 7846.1022807506. The cubic root of 61561321 is about 394.8534862268.

Adding to 61561321 its reverse (12316516), we get a palindrome (73877837).

The spelling of 61561321 in words is "sixty-one million, five hundred sixty-one thousand, three hundred twenty-one".