81612277790 has 16 divisors (see below), whose sum is σ = 146927346768. Its totient is φ = 32639300736.

The previous prime is 81612277777. The next prime is 81612277793. The reversal of 81612277790 is 9777221618.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81612277793) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 639947 + ... + 756806.

It is an arithmetic number, because the mean of its divisors is an integer number (9182959173).

Almost surely, 2^81612277790 is an apocalyptic number.

81612277790 is a deficient number, since it is larger than the sum of its proper divisors (65315068978).

81612277790 is a wasteful number, since it uses less digits than its factorization.

81612277790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1402603.

The product of its (nonzero) digits is 592704, while the sum is 50.

The spelling of 81612277790 in words is "eighty-one billion, six hundred twelve million, two hundred seventy-seven thousand, seven hundred ninety".