6645531 has 4 divisors (see below), whose sum is σ = 8860712. Its totient is φ = 4430352.

The previous prime is 6645517. The next prime is 6645547. The reversal of 6645531 is 1355466.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 6645531 - 2⁶ = 6645467 is a prime.

It is a super-2 number, since 2×6645531² = 88326164543922, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6645571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1107586 + ... + 1107591.

It is an arithmetic number, because the mean of its divisors is an integer number (2215178).

Almost surely, 2^6645531 is an apocalyptic number.

6645531 is a deficient number, since it is larger than the sum of its proper divisors (2215181).

6645531 is a wasteful number, since it uses less digits than its factorization.

6645531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2215180.

The product of its digits is 10800, while the sum is 30.

The square root of 6645531 is about 2577.8927440838. The cubic root of 6645531 is about 188.0081009788.

The spelling of 6645531 in words is "six million, six hundred forty-five thousand, five hundred thirty-one".