1604636640 has 288 divisors, whose sum is σ = 5811886080. Its totient is φ = 402029568.

The previous prime is 1604636603. The next prime is 1604636641. The reversal of 1604636640 is 466364061.

1604636640 is a `hidden beast` number, since 1 + 6 + 0 + 4 + 6 + 3 + 6 + 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 = 1604636595 and 1604636604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1604636641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 6101149 + ... + 6101411.

It is an arithmetic number, because the mean of its divisors is an integer number (20180160).

Almost surely, 2^1604636640 is an apocalyptic number.

1604636640 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 1604636640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2905943040).

1604636640 is an abundant number, since it is smaller than the sum of its proper divisors (4207249440).

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

1604636640 is a wasteful number, since it uses less digits than its factorization.

1604636640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 526 (or 515 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 1604636640 is about 40057.9160716081. The cubic root of 1604636640 is about 1170.7358071554.

The spelling of 1604636640 in words is "one billion, six hundred four million, six hundred thirty-six thousand, six hundred forty".