81139409054 has 16 divisors (see below), whose sum is σ = 132895316736. Its totient is φ = 36847733400.

The previous prime is 81139409023. The next prime is 81139409063. The reversal of 81139409054 is 45090493118.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81139408996 and 81139409014.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1666262 + ... + 1714265.

It is an arithmetic number, because the mean of its divisors is an integer number (8305957296).

Almost surely, 2^81139409054 is an apocalyptic number.

81139409054 is a deficient number, since it is larger than the sum of its proper divisors (51755907682).

81139409054 is a wasteful number, since it uses less digits than its factorization.

81139409054 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3381631.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 81139409054 in words is "eighty-one billion, one hundred thirty-nine million, four hundred nine thousand, fifty-four".