21700624111549 has 2 divisors, whose sum is σ = 21700624111550. Its totient is φ = 21700624111548.

The previous prime is 21700624111547. The next prime is 21700624111609. The reversal of 21700624111549 is 94511142600712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20409775927524 + 1290848184025 = 4517718^2 + 1136155^2 .

It is a cyclic number.

It is not a de Polignac number, because 21700624111549 - 2¹ = 21700624111547 is a prime.

Together with 21700624111547, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21700624111547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10850312055774 + 10850312055775.

It is an arithmetic number, because the mean of its divisors is an integer number (10850312055775).

Almost surely, 2^{21700624111549} is an apocalyptic number.

It is an amenable number.

21700624111549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21700624111549 is an equidigital number, since it uses as much as digits as its factorization.

21700624111549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 43.

The spelling of 21700624111549 in words is "twenty-one trillion, seven hundred billion, six hundred twenty-four million, one hundred eleven thousand, five hundred forty-nine".