21227494909 has 2 divisors, whose sum is σ = 21227494910. Its totient is φ = 21227494908.

The previous prime is 21227494861. The next prime is 21227494913. The reversal of 21227494909 is 90949472212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16714611225 + 4512883684 = 129285^2 + 67178^2 .

It is a cyclic number.

It is not a de Polignac number, because 21227494909 - 2¹¹ = 21227492861 is a prime.

It is a super-2 number, since 2×21227494909² (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 (21227494709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613747454 + 10613747455.

It is an arithmetic number, because the mean of its divisors is an integer number (10613747455).

Almost surely, 2^21227494909 is an apocalyptic number.

It is an amenable number.

21227494909 is a deficient number, since it is larger than the sum of its proper divisors (1).

21227494909 is an equidigital number, since it uses as much as digits as its factorization.

21227494909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 653184, while the sum is 49.

The spelling of 21227494909 in words is "twenty-one billion, two hundred twenty-seven million, four hundred ninety-four thousand, nine hundred nine".