81285229078 has 4 divisors (see below), whose sum is σ = 121927843620. Its totient is φ = 40642614538.

The previous prime is 81285229061. The next prime is 81285229087. The reversal of 81285229078 is 87092258218.

It is a semiprime because it is the product of two primes.

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 as a sum of consecutive naturals, namely, 20321307268 + ... + 20321307271.

It is an arithmetic number, because the mean of its divisors is an integer number (30481960905).

Almost surely, 2^81285229078 is an apocalyptic number.

81285229078 is a deficient number, since it is larger than the sum of its proper divisors (40642614542).

81285229078 is a wasteful number, since it uses less digits than its factorization.

81285229078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40642614541.

The product of its (nonzero) digits is 1290240, while the sum is 52.

The spelling of 81285229078 in words is "eighty-one billion, two hundred eighty-five million, two hundred twenty-nine thousand, seventy-eight".