81697988612241 has 20 divisors (see below), whose sum is σ = 122045229015204. Its totient is φ = 54464185641600.

The previous prime is 81697988612239. The next prime is 81697988612243. The reversal of 81697988612241 is 14221688979618.

It is an interprime number because it is at equal distance from previous prime (81697988612239) and next prime (81697988612243).

It can be written as a sum of positive squares in 2 ways, for example, as 35568150921216 + 46129837691025 = 5963904^2 + 6791895^2 .

It is not a de Polignac number, because 81697988612241 - 2¹ = 81697988612239 is a prime.

It is a super-2 number, since 2×81697988612241² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 81697988612241.

It is not an unprimeable number, because it can be changed into a prime (81697988612243) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6654180 + ... + 14410901.

Almost surely, 2^{81697988612241} is an apocalyptic number.

81697988612241 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

81697988612241 is a deficient number, since it is larger than the sum of its proper divisors (40347240402963).

81697988612241 is a wasteful number, since it uses less digits than its factorization.

81697988612241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21112974 (or 21112965 counting only the distinct ones).

The product of its digits is 167215104, while the sum is 72.

The spelling of 81697988612241 in words is "eighty-one trillion, six hundred ninety-seven billion, nine hundred eighty-eight million, six hundred twelve thousand, two hundred forty-one".