6670781 has 4 divisors (see below), whose sum is σ = 7183932. Its totient is φ = 6157632.

The previous prime is 6670771. The next prime is 6670799. The reversal of 6670781 is 1870766.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2805625 + 3865156 = 1675^2 + 1966^2 .

It is not a de Polignac number, because 6670781 - 2¹⁸ = 6408637 is a prime.

It is a super-2 number, since 2×6670781² = 88998638299922, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6670751) 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, 256556 + ... + 256581.

It is an arithmetic number, because the mean of its divisors is an integer number (1795983).

Almost surely, 2^6670781 is an apocalyptic number.

It is an amenable number.

6670781 is a deficient number, since it is larger than the sum of its proper divisors (513151).

6670781 is a wasteful number, since it uses less digits than its factorization.

6670781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 513150.

The product of its (nonzero) digits is 14112, while the sum is 35.

The square root of 6670781 is about 2582.7855118070. The cubic root of 6670781 is about 188.2459151731.

The spelling of 6670781 in words is "six million, six hundred seventy thousand, seven hundred eighty-one".