81340997 has 2 divisors, whose sum is σ = 81340998. Its totient is φ = 81340996.

The previous prime is 81340951. The next prime is 81341003. The reversal of 81340997 is 79904318.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70543201 + 10797796 = 8399^2 + 3286^2 .

It is a cyclic number.

It is not a de Polignac number, because 81340997 - 2⁸ = 81340741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81340297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40670498 + 40670499.

It is an arithmetic number, because the mean of its divisors is an integer number (40670499).

Almost surely, 2^81340997 is an apocalyptic number.

It is an amenable number.

81340997 is a deficient number, since it is larger than the sum of its proper divisors (1).

81340997 is an equidigital number, since it uses as much as digits as its factorization.

81340997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 81340997 is about 9018.9243815435. The cubic root of 81340997 is about 433.2811849803.

The spelling of 81340997 in words is "eighty-one million, three hundred forty thousand, nine hundred ninety-seven".