81136587836 has 24 divisors (see below), whose sum is σ = 150673703040. Its totient is φ = 38146749872.

The previous prime is 81136587827. The next prime is 81136587863. The reversal of 81136587836 is 63878563118.

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, 7468466 + ... + 7479321.

It is an arithmetic number, because the mean of its divisors is an integer number (6278070960).

Almost surely, 2^81136587836 is an apocalyptic number.

It is an amenable number.

81136587836 is a deficient number, since it is larger than the sum of its proper divisors (69537115204).

81136587836 is a wasteful number, since it uses less digits than its factorization.

81136587836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14947873 (or 14947871 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 56.

The spelling of 81136587836 in words is "eighty-one billion, one hundred thirty-six million, five hundred eighty-seven thousand, eight hundred thirty-six".