81418481 has 2 divisors, whose sum is σ = 81418482. Its totient is φ = 81418480.

The previous prime is 81418409. The next prime is 81418487. The reversal of 81418481 is 18481418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81360400 + 58081 = 9020^2 + 241^2 .

It is a cyclic number.

It is not a de Polignac number, because 81418481 - 2²² = 77224177 is a prime.

It is a super-2 number, since 2×81418481² = 13257938096694722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81418487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40709240 + 40709241.

It is an arithmetic number, because the mean of its divisors is an integer number (40709241).

Almost surely, 2^81418481 is an apocalyptic number.

It is an amenable number.

81418481 is a deficient number, since it is larger than the sum of its proper divisors (1).

81418481 is an equidigital number, since it uses as much as digits as its factorization.

81418481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8192, while the sum is 35.

The square root of 81418481 is about 9023.2189932418. The cubic root of 81418481 is about 433.4187199917.

Adding to 81418481 its reverse (18481418), we get a palindrome (99899899).

The spelling of 81418481 in words is "eighty-one million, four hundred eighteen thousand, four hundred eighty-one".