21554656213 has 2 divisors, whose sum is σ = 21554656214. Its totient is φ = 21554656212.

The previous prime is 21554656187. The next prime is 21554656223. The reversal of 21554656213 is 31265645512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21439694929 + 114961284 = 146423^2 + 10722^2 .

It is a cyclic number.

It is not a de Polignac number, because 21554656213 - 2²⁹ = 21017785301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21554656223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777328106 + 10777328107.

It is an arithmetic number, because the mean of its divisors is an integer number (10777328107).

Almost surely, 2^21554656213 is an apocalyptic number.

It is an amenable number.

21554656213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21554656213 is an equidigital number, since it uses as much as digits as its factorization.

21554656213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216000, while the sum is 40.

The spelling of 21554656213 in words is "twenty-one billion, five hundred fifty-four million, six hundred fifty-six thousand, two hundred thirteen".