81778480351 has 4 divisors (see below), whose sum is σ = 81859530400. Its totient is φ = 81697430304.

The previous prime is 81778480319. The next prime is 81778480397. The reversal of 81778480351 is 15308487718.

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

It is a cyclic number.

It is not a de Polignac number, because 81778480351 - 2⁵ = 81778480319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81778480151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40523511 + ... + 40525528.

It is an arithmetic number, because the mean of its divisors is an integer number (20464882600).

Almost surely, 2^81778480351 is an apocalyptic number.

81778480351 is a deficient number, since it is larger than the sum of its proper divisors (81050049).

81778480351 is a wasteful number, since it uses less digits than its factorization.

81778480351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81050048.

The product of its (nonzero) digits is 1505280, while the sum is 52.

The spelling of 81778480351 in words is "eighty-one billion, seven hundred seventy-eight million, four hundred eighty thousand, three hundred fifty-one".