640086828 has 24 divisors (see below), whose sum is σ = 1533902832. Its totient is φ = 207595584.

The previous prime is 640086823. The next prime is 640086833. The reversal of 640086828 is 828680046.

640086828 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640086823) and next prime (640086833).

It is a super-2 number, since 2×640086828² = 819422294758203168, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 640086828.

It is not an unprimeable number, because it can be changed into a prime (640086823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 720375 + ... + 721262.

It is an arithmetic number, because the mean of its divisors is an integer number (63912618).

Almost surely, 2^640086828 is an apocalyptic number.

It is an amenable number.

640086828 is an abundant number, since it is smaller than the sum of its proper divisors (893816004).

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

640086828 is a wasteful number, since it uses less digits than its factorization.

640086828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1441681 (or 1441679 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 42.

The square root of 640086828 is about 25299.9373121753. The cubic root of 640086828 is about 861.8128461786.

The spelling of 640086828 in words is "six hundred forty million, eighty-six thousand, eight hundred twenty-eight".