21225030181 has 2 divisors, whose sum is σ = 21225030182. Its totient is φ = 21225030180.

The previous prime is 21225030143. The next prime is 21225030209. The reversal of 21225030181 is 18103052212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18114737281 + 3110292900 = 134591^2 + 55770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21225030181 is a prime.

It is a super-2 number, since 2×21225030181² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21225036181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612515090 + 10612515091.

It is an arithmetic number, because the mean of its divisors is an integer number (10612515091).

Almost surely, 2^21225030181 is an apocalyptic number.

It is an amenable number.

21225030181 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225030181 is an equidigital number, since it uses as much as digits as its factorization.

21225030181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 25.

Adding to 21225030181 its reverse (18103052212), we get a palindrome (39328082393).

The spelling of 21225030181 in words is "twenty-one billion, two hundred twenty-five million, thirty thousand, one hundred eighty-one".