1640528640 has 180 divisors, whose sum is σ = 5870482464. Its totient is φ = 437446656.

The previous prime is 1640528623. The next prime is 1640528641. The reversal of 1640528640 is 468250461.

1640528640 is a `hidden beast` number, since 1 + 6 + 4 + 0 + 5 + 2 + 8 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (180).

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 = 1640528595 and 1640528604.

It is not an unprimeable number, because it can be changed into a prime (1640528641) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 95769 + ... + 111591.

Almost surely, 2^1640528640 is an apocalyptic number.

1640528640 is a gapful number since it is divisible by the number (10) 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 1640528640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2935241232).

1640528640 is an abundant number, since it is smaller than the sum of its proper divisors (4229953824).

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

1640528640 is an equidigital number, since it uses as much as digits as its factorization.

1640528640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15856 (or 15833 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 1640528640 is about 40503.4398539186. The cubic root of 1640528640 is about 1179.4004039862.

The spelling of 1640528640 in words is "one billion, six hundred forty million, five hundred twenty-eight thousand, six hundred forty".