81438229 has 2 divisors, whose sum is σ = 81438230. Its totient is φ = 81438228.

The previous prime is 81438191. The next prime is 81438281. The reversal of 81438229 is 92283418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59367025 + 22071204 = 7705^2 + 4698^2 .

It is a cyclic number.

It is not a de Polignac number, because 81438229 - 2¹¹ = 81436181 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81438029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40719114 + 40719115.

It is an arithmetic number, because the mean of its divisors is an integer number (40719115).

Almost surely, 2^81438229 is an apocalyptic number.

It is an amenable number.

81438229 is a deficient number, since it is larger than the sum of its proper divisors (1).

81438229 is an equidigital number, since it uses as much as digits as its factorization.

81438229 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 37.

The square root of 81438229 is about 9024.3132148657. The cubic root of 81438229 is about 433.4537589692.

The spelling of 81438229 in words is "eighty-one million, four hundred thirty-eight thousand, two hundred twenty-nine".