22809781 has 2 divisors, whose sum is σ = 22809782. Its totient is φ = 22809780.

The previous prime is 22809779. The next prime is 22809821. The reversal of 22809781 is 18790822.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22184100 + 625681 = 4710^2 + 791^2 .

It is a cyclic number.

It is not a de Polignac number, because 22809781 - 2¹ = 22809779 is a prime.

It is a super-2 number, since 2×22809781² = 1040572218535922, which contains 22 as substring.

Together with 22809779, it forms a pair of twin primes.

It is equal to p_1436977 and since 22809781 and 1436977 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 22809781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22809751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11404890 + 11404891.

It is an arithmetic number, because the mean of its divisors is an integer number (11404891).

Almost surely, 2^22809781 is an apocalyptic number.

It is an amenable number.

22809781 is a deficient number, since it is larger than the sum of its proper divisors (1).

22809781 is an equidigital number, since it uses as much as digits as its factorization.

22809781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 22809781 is about 4775.9586472247. The cubic root of 22809781 is about 283.6005302558.

The spelling of 22809781 in words is "twenty-two million, eight hundred nine thousand, seven hundred eighty-one".