21275123043247 has 2 divisors, whose sum is σ = 21275123043248. Its totient is φ = 21275123043246.

The previous prime is 21275123043211. The next prime is 21275123043277. The reversal of 21275123043247 is 74234032157212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21275123043247 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21275123043277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637561521623 + 10637561521624.

It is an arithmetic number, because the mean of its divisors is an integer number (10637561521624).

Almost surely, 2^{21275123043247} is an apocalyptic number.

21275123043247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21275123043247 is an equidigital number, since it uses as much as digits as its factorization.

21275123043247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 564480, while the sum is 43.

The spelling of 21275123043247 in words is "twenty-one trillion, two hundred seventy-five billion, one hundred twenty-three million, forty-three thousand, two hundred forty-seven".