781009069 has 2 divisors, whose sum is σ = 781009070. Its totient is φ = 781009068.

The previous prime is 781009057. The next prime is 781009093. The reversal of 781009069 is 960900187.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 509088969 + 271920100 = 22563^2 + 16490^2 .

It is a cyclic number.

It is not a de Polignac number, because 781009069 - 2⁵ = 781009037 is a prime.

It is a super-2 number, since 2×781009069² = 1219950331720493522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (781009039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390504534 + 390504535.

It is an arithmetic number, because the mean of its divisors is an integer number (390504535).

Almost surely, 2^781009069 is an apocalyptic number.

It is an amenable number.

781009069 is a deficient number, since it is larger than the sum of its proper divisors (1).

781009069 is an equidigital number, since it uses as much as digits as its factorization.

781009069 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 781009069 is about 27946.5394816603. The cubic root of 781009069 is about 920.9131878706.

The spelling of 781009069 in words is "seven hundred eighty-one million, nine thousand, sixty-nine".