81630651885 has 64 divisors (see below), whose sum is σ = 139594752000. Its totient is φ = 40643124480.

The previous prime is 81630651863. The next prime is 81630651911. The reversal of 81630651885 is 58815603618.

It is not a de Polignac number, because 81630651885 - 2¹² = 81630647789 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21830346 + ... + 21834084.

It is an arithmetic number, because the mean of its divisors is an integer number (2181168000).

Almost surely, 2^81630651885 is an apocalyptic number.

It is an amenable number.

81630651885 is a deficient number, since it is larger than the sum of its proper divisors (57964100115).

81630651885 is a wasteful number, since it uses less digits than its factorization.

81630651885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5426.

The product of its (nonzero) digits is 1382400, while the sum is 51.

The spelling of 81630651885 in words is "eighty-one billion, six hundred thirty million, six hundred fifty-one thousand, eight hundred eighty-five".