999780433961 has 2 divisors, whose sum is σ = 999780433962. Its totient is φ = 999780433960.

The previous prime is 999780433957. The next prime is 999780433963. The reversal of 999780433961 is 169334087999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 931060957225 + 68719476736 = 964915^2 + 262144^2 .

It is a cyclic number.

It is not a de Polignac number, because 999780433961 - 2² = 999780433957 is a prime.

It is a super-2 number, since 2×999780433961² (a number of 25 digits) contains 22 as substring.

Together with 999780433963, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 999780433891 and 999780433900.

It is not a weakly prime, because it can be changed into another prime (999780433963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499890216980 + 499890216981.

It is an arithmetic number, because the mean of its divisors is an integer number (499890216981).

Almost surely, 2^999780433961 is an apocalyptic number.

It is an amenable number.

999780433961 is a deficient number, since it is larger than the sum of its proper divisors (1).

999780433961 is an equidigital number, since it uses as much as digits as its factorization.

999780433961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 79361856, while the sum is 68.

The spelling of 999780433961 in words is "nine hundred ninety-nine billion, seven hundred eighty million, four hundred thirty-three thousand, nine hundred sixty-one".