21250225666261 has 2 divisors, whose sum is σ = 21250225666262. Its totient is φ = 21250225666260.

The previous prime is 21250225666171. The next prime is 21250225666277. The reversal of 21250225666261 is 16266652205212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21070220633361 + 180005032900 = 4590231^2 + 424270^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21250225666261 is a prime.

It is a super-2 number, since 2×21250225666261² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21250225636261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10625112833130 + 10625112833131.

It is an arithmetic number, because the mean of its divisors is an integer number (10625112833131).

Almost surely, 2^{21250225666261} is an apocalyptic number.

It is an amenable number.

21250225666261 is a deficient number, since it is larger than the sum of its proper divisors (1).

21250225666261 is an equidigital number, since it uses as much as digits as its factorization.

21250225666261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1036800, while the sum is 46.

The spelling of 21250225666261 in words is "twenty-one trillion, two hundred fifty billion, two hundred twenty-five million, six hundred sixty-six thousand, two hundred sixty-one".