780000999917 has 2 divisors, whose sum is σ = 780000999918. Its totient is φ = 780000999916.

The previous prime is 780000999913. The next prime is 780001000001. The reversal of 780000999917 is 719999000087.

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., 474264991561 + 305736008356 = 688669^2 + 552934^2 .

It is an emirp because it is prime and its reverse (719999000087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 780000999917 - 2² = 780000999913 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (780000999913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390000499958 + 390000499959.

It is an arithmetic number, because the mean of its divisors is an integer number (390000499959).

Almost surely, 2^780000999917 is an apocalyptic number.

It is an amenable number.

780000999917 is a deficient number, since it is larger than the sum of its proper divisors (1).

780000999917 is an equidigital number, since it uses as much as digits as its factorization.

780000999917 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2571912, while the sum is 59.

The spelling of 780000999917 in words is "seven hundred eighty billion, nine hundred ninety-nine thousand, nine hundred seventeen".