81697988612243 has 2 divisors, whose sum is σ = 81697988612244. Its totient is φ = 81697988612242.

The previous prime is 81697988612239. The next prime is 81697988612267. The reversal of 81697988612243 is 34221688979618.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81697988612243 - 2² = 81697988612239 is a prime.

It is a super-2 number, since 2×81697988612243² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81697988614243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40848994306121 + 40848994306122.

It is an arithmetic number, because the mean of its divisors is an integer number (40848994306122).

Almost surely, 2^{81697988612243} is an apocalyptic number.

81697988612243 is a deficient number, since it is larger than the sum of its proper divisors (1).

81697988612243 is an equidigital number, since it uses as much as digits as its factorization.

81697988612243 is an evil number, because the sum of its binary digits is even.

The product of its digits is 501645312, while the sum is 74.

The spelling of 81697988612243 in words is "eighty-one trillion, six hundred ninety-seven billion, nine hundred eighty-eight million, six hundred twelve thousand, two hundred forty-three".