225715213507621 has 2 divisors, whose sum is σ = 225715213507622. Its totient is φ = 225715213507620.

The previous prime is 225715213507579. The next prime is 225715213507673. The reversal of 225715213507621 is 126705312517522.

225715213507621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 135411739589025 + 90303473918596 = 11636655^2 + 9502814^2 .

It is a cyclic number.

It is not a de Polignac number, because 225715213507621 - 2⁷ = 225715213507493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (225715213517621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 112857606753810 + 112857606753811.

It is an arithmetic number, because the mean of its divisors is an integer number (112857606753811).

Almost surely, 2^{225715213507621} is an apocalyptic number.

It is an amenable number.

225715213507621 is a deficient number, since it is larger than the sum of its proper divisors (1).

225715213507621 is an equidigital number, since it uses as much as digits as its factorization.

225715213507621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1764000, while the sum is 49.

Subtracting from 225715213507621 its reverse (126705312517522), we obtain a palindrome (99009900990099).

The spelling of 225715213507621 in words is "two hundred twenty-five trillion, seven hundred fifteen billion, two hundred thirteen million, five hundred seven thousand, six hundred twenty-one".