21121244025457 has 2 divisors, whose sum is σ = 21121244025458. Its totient is φ = 21121244025456.

The previous prime is 21121244025383. The next prime is 21121244025473. The reversal of 21121244025457 is 75452044212112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18664551422001 + 2456692603456 = 4320249^2 + 1567384^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121244025457 is a prime.

It is a super-2 number, since 2×21121244025457² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121244065457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560622012728 + 10560622012729.

It is an arithmetic number, because the mean of its divisors is an integer number (10560622012729).

Almost surely, 2^{21121244025457} is an apocalyptic number.

It is an amenable number.

21121244025457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121244025457 is an equidigital number, since it uses as much as digits as its factorization.

21121244025457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 179200, while the sum is 40.

Adding to 21121244025457 its reverse (75452044212112), we get a palindrome (96573288237569).

The spelling of 21121244025457 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred forty-four million, twenty-five thousand, four hundred fifty-seven".