21243076957481 has 2 divisors, whose sum is σ = 21243076957482. Its totient is φ = 21243076957480.

The previous prime is 21243076957433. The next prime is 21243076957493. The reversal of 21243076957481 is 18475967034212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16221690643456 + 5021386314025 = 4027616^2 + 2240845^2 .

It is a cyclic number.

It is not a de Polignac number, because 21243076957481 - 2²⁶ = 21243009848617 is a prime.

It is a super-2 number, since 2×21243076957481² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21243076957481.

It is not a weakly prime, because it can be changed into another prime (21243076927481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10621538478740 + 10621538478741.

It is an arithmetic number, because the mean of its divisors is an integer number (10621538478741).

It is a 1-persistent number, because it is pandigital, but 2⋅21243076957481 = 42486153914962 is not.

Almost surely, 2^{21243076957481} is an apocalyptic number.

It is an amenable number.

21243076957481 is a deficient number, since it is larger than the sum of its proper divisors (1).

21243076957481 is an equidigital number, since it uses as much as digits as its factorization.

21243076957481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20321280, while the sum is 59.

The spelling of 21243076957481 in words is "twenty-one trillion, two hundred forty-three billion, seventy-six million, nine hundred fifty-seven thousand, four hundred eighty-one".