81748084778 has 16 divisors (see below), whose sum is σ = 125038532736. Its totient is φ = 40076432400.

The previous prime is 81748084777. The next prime is 81748084849. The reversal of 81748084778 is 87748084718.

It is a self number, because there is not a number n which added to its sum of digits gives 81748084778.

It is not an unprimeable number, because it can be changed into a prime (81748084771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1943726 + ... + 1985337.

It is an arithmetic number, because the mean of its divisors is an integer number (7814908296).

Almost surely, 2^81748084778 is an apocalyptic number.

81748084778 is a deficient number, since it is larger than the sum of its proper divisors (43290447958).

81748084778 is a wasteful number, since it uses less digits than its factorization.

81748084778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3929269.

The product of its (nonzero) digits is 22478848, while the sum is 62.

The spelling of 81748084778 in words is "eighty-one billion, seven hundred forty-eight million, eighty-four thousand, seven hundred seventy-eight".