81218837160 has 128 divisors (see below), whose sum is σ = 284978448000. Its totient is φ = 20518437888.

The previous prime is 81218837071. The next prime is 81218837243. The reversal of 81218837160 is 6173881218.

It is a happy number.

81218837160 is a `hidden beast` number, since 8 + 1 + 218 + 8 + 371 + 60 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1958497 + ... + 1999536.

It is an arithmetic number, because the mean of its divisors is an integer number (2226394125).

Almost surely, 2^81218837160 is an apocalyptic number.

It is an amenable number.

81218837160 is an abundant number, since it is smaller than the sum of its proper divisors (203759610840).

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

81218837160 is a wasteful number, since it uses less digits than its factorization.

81218837160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3958072 (or 3958062 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 45.

The spelling of 81218837160 in words is "eighty-one billion, two hundred eighteen million, eight hundred thirty-seven thousand, one hundred sixty".