6781690 has 8 divisors (see below), whose sum is σ = 12207060. Its totient is φ = 2712672.

The previous prime is 6781667. The next prime is 6781699. The reversal of 6781690 is 961876.

It can be written as a sum of positive squares in 2 ways, for example, as 5987809 + 793881 = 2447^2 + 891^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×6781690² = 91982638512200, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (6781699) 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, 339075 + ... + 339094.

Almost surely, 2^6781690 is an apocalyptic number.

6781690 is a deficient number, since it is larger than the sum of its proper divisors (5425370).

6781690 is a wasteful number, since it uses less digits than its factorization.

6781690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678176.

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 6781690 is about 2604.1678133331. The cubic root of 6781690 is about 189.2834506502.

The spelling of 6781690 in words is "six million, seven hundred eighty-one thousand, six hundred ninety".