780216405781 has 8 divisors (see below), whose sum is σ = 828562863960. Its totient is φ = 732142322688.

The previous prime is 780216405769. The next prime is 780216405791. The reversal of 780216405781 is 187504612087.

It can be written as a sum of positive squares in 4 ways, for example, as 40686924100 + 739529481681 = 201710^2 + 859959^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 780216405781 - 2⁷ = 780216405653 is a prime.

It is a super-2 number, since 2×780216405781² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (780216405721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68087866 + ... + 68099323.

It is an arithmetic number, because the mean of its divisors is an integer number (103570357995).

Almost surely, 2^780216405781 is an apocalyptic number.

It is an amenable number.

780216405781 is a deficient number, since it is larger than the sum of its proper divisors (48346458179).

780216405781 is a wasteful number, since it uses less digits than its factorization.

780216405781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136187543.

The product of its (nonzero) digits is 752640, while the sum is 49.

The spelling of 780216405781 in words is "seven hundred eighty billion, two hundred sixteen million, four hundred five thousand, seven hundred eighty-one".