81378135 has 16 divisors (see below), whose sum is σ = 144672480. Its totient is φ = 43401600.

The previous prime is 81378091. The next prime is 81378151. The reversal of 81378135 is 53187318.

It is not a de Polignac number, because 81378135 - 2¹⁴ = 81361751 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81378135.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 301266 + ... + 301535.

It is an arithmetic number, because the mean of its divisors is an integer number (9042030).

Almost surely, 2^81378135 is an apocalyptic number.

81378135 is a deficient number, since it is larger than the sum of its proper divisors (63294345).

81378135 is a wasteful number, since it uses less digits than its factorization.

81378135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602815 (or 602809 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 81378135 is about 9020.9830395584. The cubic root of 81378135 is about 433.3471162611.

The spelling of 81378135 in words is "eighty-one million, three hundred seventy-eight thousand, one hundred thirty-five".