6645420509 has 32 divisors (see below), whose sum is σ = 8386963200. Its totient is φ = 5124736512.

The previous prime is 6645420497. The next prime is 6645420511. The reversal of 6645420509 is 9050245466.

It is a happy number.

It is not a de Polignac number, because 6645420509 - 2⁸ = 6645420253 is a prime.

It is a super-2 number, since 2×6645420509² = 88323227482875638162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6645420709) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2178017 + ... + 2181065.

It is an arithmetic number, because the mean of its divisors is an integer number (262092600).

Almost surely, 2^6645420509 is an apocalyptic number.

It is an amenable number.

6645420509 is a deficient number, since it is larger than the sum of its proper divisors (1741542691).

6645420509 is a wasteful number, since it uses less digits than its factorization.

6645420509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3669.

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 6645420509 is about 81519.4486549069. The cubic root of 6645420509 is about 1880.0705900950.

The spelling of 6645420509 in words is "six billion, six hundred forty-five million, four hundred twenty thousand, five hundred nine".