81491156105 has 16 divisors (see below), whose sum is σ = 97963841664. Its totient is φ = 65076708480.

The previous prime is 81491156053. The next prime is 81491156167. The reversal of 81491156105 is 50165119418.

It is a de Polignac number, because none of the positive numbers 2^k-81491156105 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11666444 + ... + 11673426.

It is an arithmetic number, because the mean of its divisors is an integer number (6122740104).

Almost surely, 2^81491156105 is an apocalyptic number.

It is an amenable number.

81491156105 is a deficient number, since it is larger than the sum of its proper divisors (16472685559).

81491156105 is a wasteful number, since it uses less digits than its factorization.

81491156105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10816.

The product of its (nonzero) digits is 43200, while the sum is 41.

The spelling of 81491156105 in words is "eighty-one billion, four hundred ninety-one million, one hundred fifty-six thousand, one hundred five".