21554445511 has 2 divisors, whose sum is σ = 21554445512. Its totient is φ = 21554445510.

The previous prime is 21554445491. The next prime is 21554445527. The reversal of 21554445511 is 11554445512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21554445511 - 2⁷ = 21554445383 is a prime.

It is a super-2 number, since 2×21554445511² (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 (21554445551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777222755 + 10777222756.

It is an arithmetic number, because the mean of its divisors is an integer number (10777222756).

Almost surely, 2^21554445511 is an apocalyptic number.

21554445511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21554445511 is an equidigital number, since it uses as much as digits as its factorization.

21554445511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80000, while the sum is 37.

Subtracting from 21554445511 its reverse (11554445512), we obtain a palindrome (9999999999).

The spelling of 21554445511 in words is "twenty-one billion, five hundred fifty-four million, four hundred forty-five thousand, five hundred eleven".