81491511152 has 20 divisors (see below), whose sum is σ = 157902122040. Its totient is φ = 40742576448.

The previous prime is 81491511149. The next prime is 81491511191. The reversal of 81491511152 is 25111519418.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 20078 + ... + 404210.

It is an arithmetic number, because the mean of its divisors is an integer number (7895106102).

Almost surely, 2^81491511152 is an apocalyptic number.

It is an amenable number.

81491511152 is a deficient number, since it is larger than the sum of its proper divisors (76410610888).

81491511152 is a wasteful number, since it uses less digits than its factorization.

81491511152 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397400 (or 397394 counting only the distinct ones).

The product of its digits is 14400, while the sum is 38.

The spelling of 81491511152 in words is "eighty-one billion, four hundred ninety-one million, five hundred eleven thousand, one hundred fifty-two".