221520072461 has 2 divisors, whose sum is σ = 221520072462. Its totient is φ = 221520072460.

The previous prime is 221520072451. The next prime is 221520072463. The reversal of 221520072461 is 164270025122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 210616744900 + 10903327561 = 458930^2 + 104419^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221520072461 is a prime.

It is a super-2 number, since 2×221520072461² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 221520072463, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221520072463) 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, 110760036230 + 110760036231.

It is an arithmetic number, because the mean of its divisors is an integer number (110760036231).

Almost surely, 2^221520072461 is an apocalyptic number.

It is an amenable number.

221520072461 is a deficient number, since it is larger than the sum of its proper divisors (1).

221520072461 is an equidigital number, since it uses as much as digits as its factorization.

221520072461 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13440, while the sum is 32.

Adding to 221520072461 its reverse (164270025122), we get a palindrome (385790097583).

The spelling of 221520072461 in words is "two hundred twenty-one billion, five hundred twenty million, seventy-two thousand, four hundred sixty-one".