81249150778 has 8 divisors (see below), whose sum is σ = 125167610772. Its totient is φ = 39526613856.

The previous prime is 81249150739. The next prime is 81249150793. The reversal of 81249150778 is 87705194218.

It can be written as a sum of positive squares in 2 ways, for example, as 80716787449 + 532363329 = 284107^2 + 23073^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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, 548980675 + ... + 548980822.

Almost surely, 2^81249150778 is an apocalyptic number.

81249150778 is a deficient number, since it is larger than the sum of its proper divisors (43918459994).

81249150778 is a wasteful number, since it uses less digits than its factorization.

81249150778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1097961536.

The product of its (nonzero) digits is 1128960, while the sum is 52.

The spelling of 81249150778 in words is "eighty-one billion, two hundred forty-nine million, one hundred fifty thousand, seven hundred seventy-eight".