81401897 has 2 divisors, whose sum is σ = 81401898. Its totient is φ = 81401896.

The previous prime is 81401893. The next prime is 81401917. The reversal of 81401897 is 79810418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81342361 + 59536 = 9019^2 + 244^2 .

It is a cyclic number.

It is not a de Polignac number, because 81401897 - 2² = 81401893 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81401897.

It is not a weakly prime, because it can be changed into another prime (81401891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40700948 + 40700949.

It is an arithmetic number, because the mean of its divisors is an integer number (40700949).

Almost surely, 2^81401897 is an apocalyptic number.

It is an amenable number.

81401897 is a deficient number, since it is larger than the sum of its proper divisors (1).

81401897 is an equidigital number, since it uses as much as digits as its factorization.

81401897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 81401897 is about 9022.2999839287. The cubic root of 81401897 is about 433.3892905385.

The spelling of 81401897 in words is "eighty-one million, four hundred one thousand, eight hundred ninety-seven".