6403920 has 40 divisors (see below), whose sum is σ = 19852896. Its totient is φ = 1707648.

The previous prime is 6403907. The next prime is 6403921. The reversal of 6403920 is 293046.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6403921) 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 7 ways as a sum of consecutive naturals, for example, 13102 + ... + 13581.

Almost surely, 2^6403920 is an apocalyptic number.

6403920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6403920 is an abundant number, since it is smaller than the sum of its proper divisors (13448976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6403920 is a wasteful number, since it uses less digits than its factorization.

6403920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26699 (or 26693 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 24.

The square root of 6403920 is about 2530.5967675629. The cubic root of 6403920 is about 185.7014519167.

Adding to 6403920 its reverse (293046), we get a palindrome (6696966).

It can be divided in two parts, 640 and 3920, that added together give a triangular number (4560 = T₉₅).

The spelling of 6403920 in words is "six million, four hundred three thousand, nine hundred twenty".