21123401461 has 2 divisors, whose sum is σ = 21123401462. Its totient is φ = 21123401460.

The previous prime is 21123401423. The next prime is 21123401471. The reversal of 21123401461 is 16410432112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17585412100 + 3537989361 = 132610^2 + 59481^2 .

It is a cyclic number.

It is not a de Polignac number, because 21123401461 - 2¹¹ = 21123399413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21123401471) 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, 10561700730 + 10561700731.

It is an arithmetic number, because the mean of its divisors is an integer number (10561700731).

Almost surely, 2^21123401461 is an apocalyptic number.

It is an amenable number.

21123401461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21123401461 is an equidigital number, since it uses as much as digits as its factorization.

21123401461 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

Adding to 21123401461 its reverse (16410432112), we get a palindrome (37533833573).

The spelling of 21123401461 in words is "twenty-one billion, one hundred twenty-three million, four hundred one thousand, four hundred sixty-one".