19221281 has 2 divisors, whose sum is σ = 19221282. Its totient is φ = 19221280.

The previous prime is 19221269. The next prime is 19221299. The reversal of 19221281 is 18212291.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19140625 + 80656 = 4375^2 + 284^2 .

It is an emirp because it is prime and its reverse (18212291) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19221281 - 2¹⁴ = 19204897 is a prime.

It is a super-3 number, since 3×19221281³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 19221281.

It is not a weakly prime, because it can be changed into another prime (19221221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9610640 + 9610641.

It is an arithmetic number, because the mean of its divisors is an integer number (9610641).

Almost surely, 2^19221281 is an apocalyptic number.

It is an amenable number.

19221281 is a deficient number, since it is larger than the sum of its proper divisors (1).

19221281 is an equidigital number, since it uses as much as digits as its factorization.

19221281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 26.

The square root of 19221281 is about 4384.2081383073. The cubic root of 19221281 is about 267.8720754664.

The spelling of 19221281 in words is "nineteen million, two hundred twenty-one thousand, two hundred eighty-one".