640011840 has 112 divisors (see below), whose sum is σ = 2188390848. Its totient is φ = 157538304.

The previous prime is 640011811. The next prime is 640011847. The reversal of 640011840 is 48110046.

It is a Harshad number since it is a multiple of its sum of digits (24).

640011840 is a modest number, since divided by 11840 gives 640 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 640011840.

It is not an unprimeable number, because it can be changed into a prime (640011847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13162 + ... + 38121.

It is an arithmetic number, because the mean of its divisors is an integer number (19539204).

Almost surely, 2^640011840 is an apocalyptic number.

640011840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

640011840 is an abundant number, since it is smaller than the sum of its proper divisors (1548379008).

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

640011840 is a wasteful number, since it uses less digits than its factorization.

640011840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51316 (or 51306 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 640011840 is about 25298.4552888116. The cubic root of 640011840 is about 861.7791902522.

Adding to 640011840 its reverse (48110046), we get a palindrome (688121886).

The spelling of 640011840 in words is "six hundred forty million, eleven thousand, eight hundred forty".