21450544138207 has 2 divisors, whose sum is σ = 21450544138208. Its totient is φ = 21450544138206.

The previous prime is 21450544138201. The next prime is 21450544138217. The reversal of 21450544138207 is 70283144505412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21450544138207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21450544138201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10725272069103 + 10725272069104.

It is an arithmetic number, because the mean of its divisors is an integer number (10725272069104).

Almost surely, 2^{21450544138207} is an apocalyptic number.

21450544138207 is a deficient number, since it is larger than the sum of its proper divisors (1).

21450544138207 is an equidigital number, since it uses as much as digits as its factorization.

21450544138207 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1075200, while the sum is 46.

The spelling of 21450544138207 in words is "twenty-one trillion, four hundred fifty billion, five hundred forty-four million, one hundred thirty-eight thousand, two hundred seven".