640246420 has 96 divisors (see below), whose sum is σ = 1562198400. Its totient is φ = 217958400.

The previous prime is 640246403. The next prime is 640246429. The reversal of 640246420 is 24642046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640246429) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 371160 + ... + 372880.

It is an arithmetic number, because the mean of its divisors is an integer number (16272900).

Almost surely, 2^640246420 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640246420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (781099200).

640246420 is an abundant number, since it is smaller than the sum of its proper divisors (921951980).

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

640246420 is a wasteful number, since it uses less digits than its factorization.

640246420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1849 (or 1847 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 640246420 is about 25303.0911155139. The cubic root of 640246420 is about 861.8844651114.

Adding to 640246420 its reverse (24642046), we get a palindrome (664888466).

The spelling of 640246420 in words is "six hundred forty million, two hundred forty-six thousand, four hundred twenty".