6406521 has 16 divisors (see below), whose sum is σ = 9434880. Its totient is φ = 3834320.

The previous prime is 6406507. The next prime is 6406529. The reversal of 6406521 is 1256046.

It is a cyclic number.

It is not a de Polignac number, because 6406521 - 2⁶ = 6406457 is a prime.

It is a super-2 number, since 2×6406521² = 82087022646882, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 6406491 and 6406500.

It is not an unprimeable number, because it can be changed into a prime (6406529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1570 + ... + 3908.

It is an arithmetic number, because the mean of its divisors is an integer number (589680).

Almost surely, 2^6406521 is an apocalyptic number.

It is an amenable number.

6406521 is a deficient number, since it is larger than the sum of its proper divisors (3028359).

6406521 is a wasteful number, since it uses less digits than its factorization.

6406521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2436.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 6406521 is about 2531.1106257926. The cubic root of 6406521 is about 185.7265898582.

The spelling of 6406521 in words is "six million, four hundred six thousand, five hundred twenty-one".