21124545461 has 2 divisors, whose sum is σ = 21124545462. Its totient is φ = 21124545460.

The previous prime is 21124545391. The next prime is 21124545493. The reversal of 21124545461 is 16454542112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19250175025 + 1874370436 = 138745^2 + 43294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124545461 - 2¹⁴ = 21124529077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21124545061) 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, 10562272730 + 10562272731.

It is an arithmetic number, because the mean of its divisors is an integer number (10562272731).

Almost surely, 2^21124545461 is an apocalyptic number.

It is an amenable number.

21124545461 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124545461 is an equidigital number, since it uses as much as digits as its factorization.

21124545461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38400, while the sum is 35.

The spelling of 21124545461 in words is "twenty-one billion, one hundred twenty-four million, five hundred forty-five thousand, four hundred sixty-one".