6639761 has 4 divisors (see below), whose sum is σ = 6819252. Its totient is φ = 6460272.

The previous prime is 6639757. The next prime is 6639769. The reversal of 6639761 is 1679366.

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 6225025 + 414736 = 2495^2 + 644^2 .

It is a cyclic number.

It is not a de Polignac number, because 6639761 - 2² = 6639757 is a prime.

It is a super-2 number, since 2×6639761² = 88172852274242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6639769) 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, 89690 + ... + 89763.

It is an arithmetic number, because the mean of its divisors is an integer number (1704813).

Almost surely, 2^6639761 is an apocalyptic number.

It is an amenable number.

6639761 is a deficient number, since it is larger than the sum of its proper divisors (179491).

6639761 is a wasteful number, since it uses less digits than its factorization.

6639761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179490.

The product of its digits is 40824, while the sum is 38.

The square root of 6639761 is about 2576.7733699338. The cubic root of 6639761 is about 187.9536723783.

The spelling of 6639761 in words is "six million, six hundred thirty-nine thousand, seven hundred sixty-one".