21225007261 has 2 divisors, whose sum is σ = 21225007262. Its totient is φ = 21225007260.

The previous prime is 21225007247. The next prime is 21225007277. The reversal of 21225007261 is 16270052212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17256763225 + 3968244036 = 131365^2 + 62994^2 .

It is a cyclic number.

It is not a de Polignac number, because 21225007261 - 2¹¹ = 21225005213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21225007211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612503630 + 10612503631.

It is an arithmetic number, because the mean of its divisors is an integer number (10612503631).

Almost surely, 2^21225007261 is an apocalyptic number.

It is an amenable number.

21225007261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225007261 is an equidigital number, since it uses as much as digits as its factorization.

21225007261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

Adding to 21225007261 its reverse (16270052212), we get a palindrome (37495059473).

The spelling of 21225007261 in words is "twenty-one billion, two hundred twenty-five million, seven thousand, two hundred sixty-one".