81019397 has 2 divisors, whose sum is σ = 81019398. Its totient is φ = 81019396.

The previous prime is 81019391. The next prime is 81019429. The reversal of 81019397 is 79391018.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 79459396 + 1560001 = 8914^2 + 1249^2 .

It is a cyclic number.

It is not a de Polignac number, because 81019397 - 2⁶ = 81019333 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81019397.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81019391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40509698 + 40509699.

It is an arithmetic number, because the mean of its divisors is an integer number (40509699).

Almost surely, 2^81019397 is an apocalyptic number.

It is an amenable number.

81019397 is a deficient number, since it is larger than the sum of its proper divisors (1).

81019397 is an equidigital number, since it uses as much as digits as its factorization.

81019397 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 81019397 is about 9001.0775466052. The cubic root of 81019397 is about 432.7094057615.

The spelling of 81019397 in words is "eighty-one million, nineteen thousand, three hundred ninety-seven".