81693938635 has 4 divisors (see below), whose sum is σ = 98032726368. Its totient is φ = 65355150904.

The previous prime is 81693938519. The next prime is 81693938653. The reversal of 81693938635 is 53683939618.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81693938635 - 2⁷ = 81693938507 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8169393859 + ... + 8169393868.

It is an arithmetic number, because the mean of its divisors is an integer number (24508181592).

Almost surely, 2^81693938635 is an apocalyptic number.

81693938635 is a deficient number, since it is larger than the sum of its proper divisors (16338787733).

81693938635 is a wasteful number, since it uses less digits than its factorization.

81693938635 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16338787732.

The product of its digits is 25194240, while the sum is 61.

The spelling of 81693938635 in words is "eighty-one billion, six hundred ninety-three million, nine hundred thirty-eight thousand, six hundred thirty-five".