781320949 has 2 divisors, whose sum is σ = 781320950. Its totient is φ = 781320948.

The previous prime is 781320941. The next prime is 781320959. The reversal of 781320949 is 949023187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 555780625 + 225540324 = 23575^2 + 15018^2 .

It is a cyclic number.

It is not a de Polignac number, because 781320949 - 2³ = 781320941 is a prime.

It is a super-2 number, since 2×781320949² = 1220924850692521202, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (781320941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390660474 + 390660475.

It is an arithmetic number, because the mean of its divisors is an integer number (390660475).

Almost surely, 2^781320949 is an apocalyptic number.

It is an amenable number.

781320949 is a deficient number, since it is larger than the sum of its proper divisors (1).

781320949 is an equidigital number, since it uses as much as digits as its factorization.

781320949 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 781320949 is about 27952.1188642292. The cubic root of 781320949 is about 921.0357541736.

The spelling of 781320949 in words is "seven hundred eighty-one million, three hundred twenty thousand, nine hundred forty-nine".