81709954559999 has 16 divisors (see below), whose sum is σ = 83786472000000. Its totient is φ = 79658682073344.

The previous prime is 81709954559939. The next prime is 81709954560053. The reversal of 81709954559999 is 99995545990718.

It is a cyclic number.

It is not a de Polignac number, because 81709954559999 - 2¹² = 81709954555903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81709954559939) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 321567002 + ... + 321821000.

It is an arithmetic number, because the mean of its divisors is an integer number (5236654500000).

Almost surely, 2^{81709954559999} is an apocalyptic number.

81709954559999 is a deficient number, since it is larger than the sum of its proper divisors (2076517440001).

81709954559999 is a wasteful number, since it uses less digits than its factorization.

81709954559999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303662.

The product of its (nonzero) digits is 14880348000, while the sum is 89.

The spelling of 81709954559999 in words is "eighty-one trillion, seven hundred nine billion, nine hundred fifty-four million, five hundred fifty-nine thousand, nine hundred ninety-nine".