6640929 has 9 divisors (see below), whose sum is σ = 9603633. Its totient is φ = 4422132.

The previous prime is 6640927. The next prime is 6640939. The reversal of 6640929 is 9290466.

The square root of 6640929 is 2577.

It is a perfect power (a square), and thus also a powerful number.

6640929 is a `hidden beast` number, since 6 + 640 + 9 + 2 + 9 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 6640929 - 2¹ = 6640927 is a prime.

It is a super-3 number, since 3×6640929³ (a number of 21 digits) contains 333 as substring.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 6640893 and 6640902.

It is not an unprimeable number, because it can be changed into a prime (6640927) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7302 + ... + 8160.

Almost surely, 2^6640929 is an apocalyptic number.

6640929 is the 2577-th square number.

6640929 is the 1289-th centered octagonal number.

It is an amenable number.

6640929 is a deficient number, since it is larger than the sum of its proper divisors (2962704).

6640929 is an frugal number, since it uses more digits than its factorization.

6640929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1724 (or 862 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The cubic root of 6640929 is about 187.9646927056.

Multiplying 6640929 by its sum of digits (36), we get a square (239073444 = 15462²).

It can be divided in two parts, 6640 and 929, that added together give a square (7569 = 87²).

The spelling of 6640929 in words is "six million, six hundred forty thousand, nine hundred twenty-nine".