681689473 has 4 divisors (see below), whose sum is σ = 703679488. Its totient is φ = 659699460.

The previous prime is 681689471. The next prime is 681689483. The reversal of 681689473 is 374986186.

It is a happy number.

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 681689473 - 2¹ = 681689471 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 681689473.

It is not an unprimeable number, because it can be changed into a prime (681689471) 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, 10994961 + ... + 10995022.

It is an arithmetic number, because the mean of its divisors is an integer number (175919872).

Almost surely, 2^681689473 is an apocalyptic number.

It is an amenable number.

681689473 is a deficient number, since it is larger than the sum of its proper divisors (21990015).

681689473 is a wasteful number, since it uses less digits than its factorization.

681689473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21990014.

The product of its digits is 1741824, while the sum is 52.

The square root of 681689473 is about 26109.1836908012. The cubic root of 681689473 is about 880.0935992900.

The spelling of 681689473 in words is "six hundred eighty-one million, six hundred eighty-nine thousand, four hundred seventy-three".