81418937 has 2 divisors, whose sum is σ = 81418938. Its totient is φ = 81418936.

The previous prime is 81418913. The next prime is 81418943. The reversal of 81418937 is 73981418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81072016 + 346921 = 9004^2 + 589^2 .

It is a cyclic number.

It is not a de Polignac number, because 81418937 - 2⁸ = 81418681 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81418894 and 81418903.

It is not a weakly prime, because it can be changed into another prime (81418037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40709468 + 40709469.

It is an arithmetic number, because the mean of its divisors is an integer number (40709469).

Almost surely, 2^81418937 is an apocalyptic number.

It is an amenable number.

81418937 is a deficient number, since it is larger than the sum of its proper divisors (1).

81418937 is an equidigital number, since it uses as much as digits as its factorization.

81418937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48384, while the sum is 41.

The square root of 81418937 is about 9023.2442613508. The cubic root of 81418937 is about 433.4195291387.

The spelling of 81418937 in words is "eighty-one million, four hundred eighteen thousand, nine hundred thirty-seven".