6639769 has 2 divisors, whose sum is σ = 6639770. Its totient is φ = 6639768.

The previous prime is 6639757. The next prime is 6639799. The reversal of 6639769 is 9679366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4897369 + 1742400 = 2213^2 + 1320^2 .

It is a cyclic number.

It is not a de Polignac number, because 6639769 - 2⁷ = 6639641 is a prime.

It is a super-2 number, since 2×6639769² = 88173064746722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (6639719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319884 + 3319885.

It is an arithmetic number, because the mean of its divisors is an integer number (3319885).

Almost surely, 2^6639769 is an apocalyptic number.

It is an amenable number.

6639769 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639769 is an equidigital number, since it uses as much as digits as its factorization.

6639769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 367416, while the sum is 46.

The square root of 6639769 is about 2576.7749222623. The cubic root of 6639769 is about 187.9537478644.

It can be divided in two parts, 66397 and 69, that added together give a palindrome (66466).

The spelling of 6639769 in words is "six million, six hundred thirty-nine thousand, seven hundred sixty-nine".