420646640 has 80 divisors (see below), whose sum is σ = 1059762528. Its totient is φ = 154656768.

The previous prime is 420646631. The next prime is 420646649. The reversal of 420646640 is 46646024.

It is an interprime number because it is at equal distance from previous prime (420646631) and next prime (420646649).

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

It is a junction number, because it is equal to n+sod(n) for n = 420646597 and 420646606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420646649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54884 + ... + 62076.

Almost surely, 2^420646640 is an apocalyptic number.

420646640 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 420646640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (529881264).

420646640 is an abundant number, since it is smaller than the sum of its proper divisors (639115888).

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

420646640 is a wasteful number, since it uses less digits than its factorization.

420646640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7266 (or 7260 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 420646640 is about 20509.6718647569. The cubic root of 420646640 is about 749.2713753337.

The spelling of 420646640 in words is "four hundred twenty million, six hundred forty-six thousand, six hundred forty".