61211221 has 2 divisors, whose sum is σ = 61211222. Its totient is φ = 61211220.

The previous prime is 61211207. The next prime is 61211233. The reversal of 61211221 is 12211216.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56415121 + 4796100 = 7511^2 + 2190^2 .

It is a cyclic number.

It is not a de Polignac number, because 61211221 - 2⁷ = 61211093 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61211195 and 61211204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61211251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30605610 + 30605611.

It is an arithmetic number, because the mean of its divisors is an integer number (30605611).

Almost surely, 2^61211221 is an apocalyptic number.

It is an amenable number.

61211221 is a deficient number, since it is larger than the sum of its proper divisors (1).

61211221 is an equidigital number, since it uses as much as digits as its factorization.

61211221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 16.

The square root of 61211221 is about 7823.7600295510. The cubic root of 61211221 is about 394.1035505609.

Adding to 61211221 its reverse (12211216), we get a palindrome (73422437).

The spelling of 61211221 in words is "sixty-one million, two hundred eleven thousand, two hundred twenty-one".