21201223120457 has 2 divisors, whose sum is σ = 21201223120458. Its totient is φ = 21201223120456.

The previous prime is 21201223120411. The next prime is 21201223120487. The reversal of 21201223120457 is 75402132210212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15059529796921 + 6141693323536 = 3880661^2 + 2478244^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201223120457 - 2²⁴ = 21201206343241 is a prime.

It is not a weakly prime, because it can be changed into another prime (21201223120487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600611560228 + 10600611560229.

It is an arithmetic number, because the mean of its divisors is an integer number (10600611560229).

Almost surely, 2^{21201223120457} is an apocalyptic number.

It is an amenable number.

21201223120457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201223120457 is an equidigital number, since it uses as much as digits as its factorization.

21201223120457 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 21201223120457 its reverse (75402132210212), we get a palindrome (96603355330669).

The spelling of 21201223120457 in words is "twenty-one trillion, two hundred one billion, two hundred twenty-three million, one hundred twenty thousand, four hundred fifty-seven".