6429840 has 80 divisors (see below), whose sum is σ = 20260608. Its totient is φ = 1686528.

The previous prime is 6429799. The next prime is 6429869. The reversal of 6429840 is 489246.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17337 + ... + 17703.

Almost surely, 2^6429840 is an apocalyptic number.

6429840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6429840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10130304).

6429840 is an abundant number, since it is smaller than the sum of its proper divisors (13830768).

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

6429840 is a wasteful number, since it uses less digits than its factorization.

6429840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456 (or 450 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 6429840 is about 2535.7129175047. The cubic root of 6429840 is about 185.9516581503.

The spelling of 6429840 in words is "six million, four hundred twenty-nine thousand, eight hundred forty".