81100787523 has 32 divisors (see below), whose sum is σ = 125979328512. Its totient is φ = 45451207200.

The previous prime is 81100787497. The next prime is 81100787533. The reversal of 81100787523 is 32578700118.

It is a Cunningham number, because it is equal to 284782²-1.

It is not a de Polignac number, because 81100787523 - 2¹⁰ = 81100786499 is a prime.

It is a super-4 number, since 4×81100787523⁴ (a number of 45 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (81100787533) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 142390 + ... + 427172.

It is an arithmetic number, because the mean of its divisors is an integer number (3936854016).

Almost surely, 2^81100787523 is an apocalyptic number.

81100787523 is a deficient number, since it is larger than the sum of its proper divisors (44878540989).

81100787523 is a wasteful number, since it uses less digits than its factorization.

81100787523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285055.

The product of its (nonzero) digits is 94080, while the sum is 42.

The spelling of 81100787523 in words is "eighty-one billion, one hundred million, seven hundred eighty-seven thousand, five hundred twenty-three".