420640 has 48 divisors (see below), whose sum is σ = 1088640. Its totient is φ = 152320.

The previous prime is 420613. The next prime is 420671. The reversal of 420640 is 46024.

420640 = 59² + 60² + ... + 113².

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1641 + ... + 1879.

It is an arithmetic number, because the mean of its divisors is an integer number (22680).

2⁴²⁰⁶⁴⁰ is an apocalyptic number.

420640 is a gapful number since it is divisible by the number (40) 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 420640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (544320).

420640 is an abundant number, since it is smaller than the sum of its proper divisors (668000).

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

420640 is a wasteful number, since it uses less digits than its factorization.

420640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 420640 is about 648.5676526007. The cubic root of 420640 is about 74.9267432842.

Adding to 420640 its reverse (46024), we get a palindrome (466664).

The spelling of 420640 in words is "four hundred twenty thousand, six hundred forty".