81178640331 has 8 divisors (see below), whose sum is σ = 108274852560. Its totient is φ = 54100760832.

The previous prime is 81178640297. The next prime is 81178640357. The reversal of 81178640331 is 13304687118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81178640331 - 2¹¹ = 81178638283 is a prime.

It is a super-2 number, since 2×81178640331² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81178640371) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4572846 + ... + 4590563.

It is an arithmetic number, because the mean of its divisors is an integer number (13534356570).

Almost surely, 2^81178640331 is an apocalyptic number.

81178640331 is a deficient number, since it is larger than the sum of its proper divisors (27096212229).

81178640331 is a wasteful number, since it uses less digits than its factorization.

81178640331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9166365.

The product of its (nonzero) digits is 96768, while the sum is 42.

The spelling of 81178640331 in words is "eighty-one billion, one hundred seventy-eight million, six hundred forty thousand, three hundred thirty-one".