781089 has 4 divisors (see below), whose sum is σ = 1041456. Its totient is φ = 520724.

The previous prime is 781087. The next prime is 781111. The reversal of 781089 is 980187.

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 781089 - 2¹ = 781087 is a prime.

It is a super-2 number, since 2×781089² = 1220200051842, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

781089 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (781087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130179 + ... + 130184.

It is an arithmetic number, because the mean of its divisors is an integer number (260364).

2⁷⁸¹⁰⁸⁹ is an apocalyptic number.

It is an amenable number.

781089 is a deficient number, since it is larger than the sum of its proper divisors (260367).

781089 is a wasteful number, since it uses less digits than its factorization.

781089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260366.

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 781089 is about 883.7923964371. The cubic root of 781089 is about 92.0944603213.

The spelling of 781089 in words is "seven hundred eighty-one thousand, eighty-nine".