780785390981 has 2 divisors, whose sum is σ = 780785390982. Its totient is φ = 780785390980.

The previous prime is 780785390963. The next prime is 780785391077. The reversal of 780785390981 is 189093587087.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 605859856900 + 174925534081 = 778370^2 + 418241^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-780785390981 is a prime.

It is a super-2 number, since 2×780785390981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (780785390381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390392695490 + 390392695491.

It is an arithmetic number, because the mean of its divisors is an integer number (390392695491).

Almost surely, 2^780785390981 is an apocalyptic number.

It is an amenable number.

780785390981 is a deficient number, since it is larger than the sum of its proper divisors (1).

780785390981 is an equidigital number, since it uses as much as digits as its factorization.

780785390981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30481920, while the sum is 65.

The spelling of 780785390981 in words is "seven hundred eighty billion, seven hundred eighty-five million, three hundred ninety thousand, nine hundred eighty-one".