21222154549 has 2 divisors, whose sum is σ = 21222154550. Its totient is φ = 21222154548.

The previous prime is 21222154543. The next prime is 21222154559. The reversal of 21222154549 is 94545122212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19045932049 + 2176222500 = 138007^2 + 46650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21222154549 - 2⁵ = 21222154517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21222154543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10611077274 + 10611077275.

It is an arithmetic number, because the mean of its divisors is an integer number (10611077275).

Almost surely, 2^21222154549 is an apocalyptic number.

It is an amenable number.

21222154549 is a deficient number, since it is larger than the sum of its proper divisors (1).

21222154549 is an equidigital number, since it uses as much as digits as its factorization.

21222154549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 57600, while the sum is 37.

The spelling of 21222154549 in words is "twenty-one billion, two hundred twenty-two million, one hundred fifty-four thousand, five hundred forty-nine".