780869861 has 2 divisors, whose sum is σ = 780869862. Its totient is φ = 780869860.

The previous prime is 780869851. The next prime is 780869899. The reversal of 780869861 is 168968087.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 453477025 + 327392836 = 21295^2 + 18094^2 .

It is a cyclic number.

It is not a de Polignac number, because 780869861 - 2¹⁴ = 780853477 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (780869821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390434930 + 390434931.

It is an arithmetic number, because the mean of its divisors is an integer number (390434931).

Almost surely, 2^780869861 is an apocalyptic number.

It is an amenable number.

780869861 is a deficient number, since it is larger than the sum of its proper divisors (1).

780869861 is an equidigital number, since it uses as much as digits as its factorization.

780869861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1161216, while the sum is 53.

The square root of 780869861 is about 27944.0487581882. The cubic root of 780869861 is about 920.8584697264.

The spelling of 780869861 in words is "seven hundred eighty million, eight hundred sixty-nine thousand, eight hundred sixty-one".