81698146681 has 2 divisors, whose sum is σ = 81698146682. Its totient is φ = 81698146680.

The previous prime is 81698146631. The next prime is 81698146787. The reversal of 81698146681 is 18664189618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80576499600 + 1121647081 = 283860^2 + 33491^2 .

It is a cyclic number.

It is not a de Polignac number, because 81698146681 - 2⁷ = 81698146553 is a prime.

It is a super-2 number, since 2×81698146681² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81698146631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40849073340 + 40849073341.

It is an arithmetic number, because the mean of its divisors is an integer number (40849073341).

Almost surely, 2^81698146681 is an apocalyptic number.

It is an amenable number.

81698146681 is a deficient number, since it is larger than the sum of its proper divisors (1).

81698146681 is an equidigital number, since it uses as much as digits as its factorization.

81698146681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3981312, while the sum is 58.

The spelling of 81698146681 in words is "eighty-one billion, six hundred ninety-eight million, one hundred forty-six thousand, six hundred eighty-one".