640229820 has 24 divisors (see below), whose sum is σ = 1792643664. Its totient is φ = 170727936.

The previous prime is 640229819. The next prime is 640229861. The reversal of 640229820 is 28922046.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5335189 + ... + 5335308.

It is an arithmetic number, because the mean of its divisors is an integer number (74693486).

Almost surely, 2^640229820 is an apocalyptic number.

640229820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640229820 is an abundant number, since it is smaller than the sum of its proper divisors (1152413844).

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

640229820 is a wasteful number, since it uses less digits than its factorization.

640229820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10670509 (or 10670507 counting only the distinct ones).

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

The square root of 640229820 is about 25302.7630902240. The cubic root of 640229820 is about 861.8770162057.

The spelling of 640229820 in words is "six hundred forty million, two hundred twenty-nine thousand, eight hundred twenty".