781684081 has 4 divisors (see below), whose sum is σ = 786364992. Its totient is φ = 777003172.

The previous prime is 781684037. The next prime is 781684091. The reversal of 781684081 is 180486187.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 781684081 - 2¹⁷ = 781553009 is a prime.

It is a super-2 number, since 2×781684081² = 1222060004977629122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (781684031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2340205 + ... + 2340538.

It is an arithmetic number, because the mean of its divisors is an integer number (196591248).

Almost surely, 2^781684081 is an apocalyptic number.

It is an amenable number.

781684081 is a deficient number, since it is larger than the sum of its proper divisors (4680911).

781684081 is a wasteful number, since it uses less digits than its factorization.

781684081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4680910.

The product of its (nonzero) digits is 86016, while the sum is 43.

The square root of 781684081 is about 27958.6137174217. The cubic root of 781684081 is about 921.1784210057.

The spelling of 781684081 in words is "seven hundred eighty-one million, six hundred eighty-four thousand, eighty-one".