81599340669 has 48 divisors (see below), whose sum is σ = 137702186496. Its totient is φ = 41756061600.

The previous prime is 81599340631. The next prime is 81599340673. The reversal of 81599340669 is 96604399518.

It is not a de Polignac number, because 81599340669 - 2²¹ = 81597243517 is a prime.

It is a super-2 number, since 2×81599340669² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81599340629) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 997614 + ... + 1076304.

It is an arithmetic number, because the mean of its divisors is an integer number (2868795552).

Almost surely, 2^81599340669 is an apocalyptic number.

It is an amenable number.

81599340669 is a deficient number, since it is larger than the sum of its proper divisors (56102845827).

81599340669 is a wasteful number, since it uses less digits than its factorization.

81599340669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78846 (or 78779 counting only the distinct ones).

The product of its (nonzero) digits is 12597120, while the sum is 60.

The spelling of 81599340669 in words is "eighty-one billion, five hundred ninety-nine million, three hundred forty thousand, six hundred sixty-nine".