81188954665 has 32 divisors (see below), whose sum is σ = 119941355520. Its totient is φ = 51376425984.

The previous prime is 81188954633. The next prime is 81188954689. The reversal of 81188954665 is 56645988118.

It is not a de Polignac number, because 81188954665 - 2⁵ = 81188954633 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1879176 + ... + 1921894.

It is an arithmetic number, because the mean of its divisors is an integer number (3748167360).

Almost surely, 2^81188954665 is an apocalyptic number.

It is an amenable number.

81188954665 is a deficient number, since it is larger than the sum of its proper divisors (38752400855).

81188954665 is a wasteful number, since it uses less digits than its factorization.

81188954665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46921.

The product of its digits is 16588800, while the sum is 61.

The spelling of 81188954665 in words is "eighty-one billion, one hundred eighty-eight million, nine hundred fifty-four thousand, six hundred sixty-five".