81178660 has 12 divisors (see below), whose sum is σ = 170475228. Its totient is φ = 32471456.

The previous prime is 81178651. The next prime is 81178709. The reversal of 81178660 is 6687118.

It can be written as a sum of positive squares in 2 ways, for example, as 27625536 + 53553124 = 5256^2 + 7318^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2029447 + ... + 2029486.

It is an arithmetic number, because the mean of its divisors is an integer number (14206269).

Almost surely, 2^81178660 is an apocalyptic number.

It is an amenable number.

81178660 is an abundant number, since it is smaller than the sum of its proper divisors (89296568).

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

81178660 is a wasteful number, since it uses less digits than its factorization.

81178660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4058942 (or 4058940 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 81178660 is about 9009.9200884359. The cubic root of 81178660 is about 432.9927514534.

The spelling of 81178660 in words is "eighty-one million, one hundred seventy-eight thousand, six hundred sixty".