22531781 has 2 divisors, whose sum is σ = 22531782. Its totient is φ = 22531780.

The previous prime is 22531759. The next prime is 22531801. The reversal of 22531781 is 18713522.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22420225 + 111556 = 4735^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 22531781 - 2¹⁰ = 22530757 is a prime.

It is a super-2 number, since 2×22531781² = 1015362310063922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22531711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11265890 + 11265891.

It is an arithmetic number, because the mean of its divisors is an integer number (11265891).

Almost surely, 2^22531781 is an apocalyptic number.

It is an amenable number.

22531781 is a deficient number, since it is larger than the sum of its proper divisors (1).

22531781 is an equidigital number, since it uses as much as digits as its factorization.

22531781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3360, while the sum is 29.

The square root of 22531781 is about 4746.7653196677. The cubic root of 22531781 is about 282.4436664240.

The spelling of 22531781 in words is "twenty-two million, five hundred thirty-one thousand, seven hundred eighty-one".