6730781 has 4 divisors (see below), whose sum is σ = 6912732. Its totient is φ = 6548832.

The previous prime is 6730771. The next prime is 6730783. The reversal of 6730781 is 1870376.

6730781 = 1834² + 1835².

It is a happy number.

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 3363556 + 3367225 = 1834^2 + 1835^2 .

It is a cyclic number.

It is not a de Polignac number, because 6730781 - 2²² = 2536477 is a prime.

It is a super-2 number, since 2×6730781² = 90606825739922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6730783) 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, 90920 + ... + 90993.

It is an arithmetic number, because the mean of its divisors is an integer number (1728183).

Almost surely, 2^6730781 is an apocalyptic number.

6730781 is the 1835-th centered square number.

It is an amenable number.

6730781 is a deficient number, since it is larger than the sum of its proper divisors (181951).

6730781 is a wasteful number, since it uses less digits than its factorization.

6730781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181950.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 6730781 is about 2594.3748765358. The cubic root of 6730781 is about 188.8086208868.

The spelling of 6730781 in words is "six million, seven hundred thirty thousand, seven hundred eighty-one".