681219509 has 4 divisors (see below), whose sum is σ = 684220704. Its totient is φ = 678218316.

The previous prime is 681219493. The next prime is 681219533. The reversal of 681219509 is 905912186.

It is a happy number.

681219509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 681219509 - 2⁴ = 681219493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (681219809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500257 + ... + 1500710.

It is an arithmetic number, because the mean of its divisors is an integer number (171055176).

Almost surely, 2^681219509 is an apocalyptic number.

It is an amenable number.

681219509 is a deficient number, since it is larger than the sum of its proper divisors (3001195).

681219509 is a wasteful number, since it uses less digits than its factorization.

681219509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3001194.

The product of its (nonzero) digits is 38880, while the sum is 41.

The square root of 681219509 is about 26100.1821641153. The cubic root of 681219509 is about 879.8913041539.

The spelling of 681219509 in words is "six hundred eighty-one million, two hundred nineteen thousand, five hundred nine".