6440240628 has 72 divisors (see below), whose sum is σ = 17277099840. Its totient is φ = 2015781120.

The previous prime is 6440240623. The next prime is 6440240633. The reversal of 6440240628 is 8260420446.

It is a happy number.

6440240628 is a `hidden beast` number, since 6 + 4 + 4 + 0 + 24 + 0 + 628 = 666.

It is an interprime number because it is at equal distance from previous prime (6440240623) and next prime (6440240633).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6440240592 and 6440240601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6440240621) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 256683 + ... + 280653.

It is an arithmetic number, because the mean of its divisors is an integer number (239959720).

Almost surely, 2^6440240628 is an apocalyptic number.

6440240628 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6440240628, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8638549920).

6440240628 is an abundant number, since it is smaller than the sum of its proper divisors (10836859212).

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

6440240628 is a wasteful number, since it uses less digits than its factorization.

6440240628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24437 (or 24432 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 36.

The square root of 6440240628 is about 80251.1098241015. The cubic root of 6440240628 is about 1860.5186656224.

The spelling of 6440240628 in words is "six billion, four hundred forty million, two hundred forty thousand, six hundred twenty-eight".