81116542620 has 36 divisors (see below), whose sum is σ = 246053513160. Its totient is φ = 21631077984.

The previous prime is 81116542609. The next prime is 81116542621. The reversal of 81116542620 is 2624561118.

It is a happy number.

81116542620 is a `hidden beast` number, since 8 + 11 + 16 + 5 + 4 + 2 + 620 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81116542621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 225323550 + ... + 225323909.

It is an arithmetic number, because the mean of its divisors is an integer number (6834819810).

Almost surely, 2^81116542620 is an apocalyptic number.

It is an amenable number.

81116542620 is an abundant number, since it is smaller than the sum of its proper divisors (164936970540).

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

81116542620 is a wasteful number, since it uses less digits than its factorization.

81116542620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450647474 (or 450647469 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The spelling of 81116542620 in words is "eighty-one billion, one hundred sixteen million, five hundred forty-two thousand, six hundred twenty".