3928400640 has 288 divisors, whose sum is σ = 14035412160. Its totient is φ = 1040449536.

The previous prime is 3928400617. The next prime is 3928400669. The reversal of 3928400640 is 460048293.

It is a happy number.

3928400640 is a `hidden beast` number, since 3 + 9 + 2 + 8 + 4 + 0 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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 = 3928400595 and 3928400604.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6808032 + ... + 6808608.

It is an arithmetic number, because the mean of its divisors is an integer number (48734070).

Almost surely, 2^3928400640 is an apocalyptic number.

3928400640 is a gapful number since it is divisible by the number (30) 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 3928400640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7017706080).

3928400640 is an abundant number, since it is smaller than the sum of its proper divisors (10107011520).

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

3928400640 is a wasteful number, since it uses less digits than its factorization.

3928400640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804 (or 784 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 3928400640 is about 62676.9546165096. The cubic root of 3928400640 is about 1577.8725626820.

The spelling of 3928400640 in words is "three billion, nine hundred twenty-eight million, four hundred thousand, six hundred forty".