21124545493 has 2 divisors, whose sum is σ = 21124545494. Its totient is φ = 21124545492.

The previous prime is 21124545461. The next prime is 21124545503. The reversal of 21124545493 is 39454542112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20840387044 + 284158449 = 144362^2 + 16857^2 .

It is a cyclic number.

It is not a de Polignac number, because 21124545493 - 2⁵ = 21124545461 is a prime.

It is a super-2 number, since 2×21124545493² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21124545193) 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, 10562272746 + 10562272747.

It is an arithmetic number, because the mean of its divisors is an integer number (10562272747).

Almost surely, 2^21124545493 is an apocalyptic number.

It is an amenable number.

21124545493 is a deficient number, since it is larger than the sum of its proper divisors (1).

21124545493 is an equidigital number, since it uses as much as digits as its factorization.

21124545493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 172800, while the sum is 40.

The spelling of 21124545493 in words is "twenty-one billion, one hundred twenty-four million, five hundred forty-five thousand, four hundred ninety-three".