6401540 has 24 divisors (see below), whose sum is σ = 13497792. Its totient is φ = 2550240.

The previous prime is 6401533. The next prime is 6401543. The reversal of 6401540 is 451046.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (6401543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6137 + ... + 7103.

It is an arithmetic number, because the mean of its divisors is an integer number (562408).

Almost surely, 2^6401540 is an apocalyptic number.

It is an amenable number.

6401540 is an abundant number, since it is smaller than the sum of its proper divisors (7096252).

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

6401540 is a wasteful number, since it uses less digits than its factorization.

6401540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1307 (or 1305 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 6401540 is about 2530.1264790520. The cubic root of 6401540 is about 185.6784439144.

Adding to 6401540 its reverse (451046), we get a palindrome (6852586).

The spelling of 6401540 in words is "six million, four hundred one thousand, five hundred forty".