81804751085 has 16 divisors (see below), whose sum is σ = 103379276160. Its totient is φ = 61971215040.

The previous prime is 81804751081. The next prime is 81804751087. The reversal of 81804751085 is 58015740818.

It is not a de Polignac number, because 81804751085 - 2² = 81804751081 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81804751081) 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, 15680 + ... + 404790.

It is an arithmetic number, because the mean of its divisors is an integer number (6461204760).

Almost surely, 2^81804751085 is an apocalyptic number.

It is an amenable number.

81804751085 is a deficient number, since it is larger than the sum of its proper divisors (21574525075).

81804751085 is a wasteful number, since it uses less digits than its factorization.

81804751085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391348.

The product of its (nonzero) digits is 358400, while the sum is 47.

The spelling of 81804751085 in words is "eighty-one billion, eight hundred four million, seven hundred fifty-one thousand, eighty-five".