81786636372 has 60 divisors (see below), whose sum is σ = 222628230496. Its totient is φ = 23367602160.

The previous prime is 81786636367. The next prime is 81786636397. The reversal of 81786636372 is 27363668718.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1390504 + ... + 1448127.

Almost surely, 2^81786636372 is an apocalyptic number.

It is an amenable number.

81786636372 is an abundant number, since it is smaller than the sum of its proper divisors (140841594124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81786636372 is a wasteful number, since it uses less digits than its factorization.

81786636372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2838666 (or 2838643 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 57.

The spelling of 81786636372 in words is "eighty-one billion, seven hundred eighty-six million, six hundred thirty-six thousand, three hundred seventy-two".