640014021 has 32 divisors (see below), whose sum is σ = 1003728000. Its totient is φ = 402361344.

The previous prime is 640014017. The next prime is 640014043. The reversal of 640014021 is 120410046.

640014021 is a `hidden beast` number, since 640 + 0 + 1 + 4 + 0 + 21 = 666.

640014021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640014021 - 2² = 640014017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640013985 and 640014003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640014091) 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, 24165 + ... + 43173.

It is an arithmetic number, because the mean of its divisors is an integer number (31366500).

Almost surely, 2^640014021 is an apocalyptic number.

It is an amenable number.

640014021 is a deficient number, since it is larger than the sum of its proper divisors (363713979).

640014021 is a wasteful number, since it uses less digits than its factorization.

640014021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19090 (or 19084 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 640014021 is about 25298.4983941735. The cubic root of 640014021 is about 861.7801691603.

Adding to 640014021 its reverse (120410046), we get a palindrome (760424067).

The spelling of 640014021 in words is "six hundred forty million, fourteen thousand, twenty-one".