81078240137920 has 28 divisors (see below), whose sum is σ = 193067559329184. Its totient is φ = 32431296055040.

The previous prime is 81078240137831. The next prime is 81078240138097. The reversal of 81078240137920 is 2973104287018.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126684749896 + ... + 126684750535.

Almost surely, 2^{81078240137920} is an apocalyptic number.

81078240137920 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81078240137920 is an abundant number, since it is smaller than the sum of its proper divisors (111989319191264).

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

81078240137920 is a wasteful number, since it uses less digits than its factorization.

81078240137920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253369500448 (or 253369500438 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 52.

The spelling of 81078240137920 in words is "eighty-one trillion, seventy-eight billion, two hundred forty million, one hundred thirty-seven thousand, nine hundred twenty".